21 ms·

2-in-1 calculator app adds up to surprise hit for retired engineer

979 points by CrankyBear 4y ago

abrax3141 4y ago
Seems like if you allowed swapping out a background set of sub calculators, and provide inter-calculator ops on the front two, you’ve recreated an elegant cross between the RPN and standard calculator models.
PaulHoule 4y ago
"The number of downloads grew at a sluggish pace at first because the app was designed so that just one calculator is displayed on the smartphone's vertical screen mode, while two are shown only when the screen is rotated on its side. So, many users only thought it was a regular calculator."
jqpabc123 4y ago
So is this significantly better than just using store and recall?
- flowerbreeze 4y ago
  In my opinion it is, because I don't need to recall what I recall.
  - jqpabc123 4y ago
    When I need to recall what I recall, I just hit [MR].
    - hn_throwaway_99 4y ago
      Which causes you to then lose what you have typed in the screen already. TBH, these semi-snarky "How is this any different from MS/MR?" responses are like "Why should a CPU ever need more than 2 registers?" to me.
      - tremon 4y ago
        But then, why should my phone screen be limited to only 2 calculators?
        jqpabc123 4y ago
        Instead of more calculators, all you really need is just better design. See above.
      - jqpabc123 4y ago
        Which causes you to then lose what you have typed in the screen already. Then hit [MX] instead. Problem solved with 1 button instead of a whole extra calculator. "Why should a CPU ever need more than 2 registers?" The question in this case is "Why should a calculator only have 2 registers". This approach doesn't scale beyond 2 numbers? Personally, I prefer RPN where I have a whole stack to work with.
        hn_throwaway_99 4y ago
        What is the [MX] button? I don't think I've ever seen that on a calculator. TBH, though, this is still kind of like arguing that people should never need GUIs because you can do everything on the command line. There is a pretty obvious, fundamental difference being able to see everything on the screen at the same time, vs having to remember what you stored in memory (and what calculations went into it). As for RPN, while I agree most people are never taught RPN.
        jqpabc123 4y ago
        [MX] = Memory Exchange --- Swap display and memory A better, more intuitive solution than any of the above with available screen real estate is a history tape of prior resultants created automatically. Multiple prior resultants (not just 2) always available to view --- no action required. To recall a number from the tape into the active accumulator for further manipulation, simply click the number. To remove a number from the tape, click and drag right or left. To reorder, click and drag up or down.
- naikrovek 4y ago
  in terms of ease of use and visibility yes I would say this is more than significantly better.
- criddell 4y ago
  It’s only $3. How much better does it need to be to be worth $3?
  - jqpabc123 4y ago
    What happens if I am working with 3 or 4 different values? This duplicate calculator method doesn't scale too well. A history tape is a better option --- just as intuitative but more capable/flexible.
    - criddell 4y ago
      Are you looking for people to tell you this is what you should be using? If it doesn't work for you, then use something else.
    - outworlder 4y ago
      Then you start approaching spreadsheet territory.
      - jqpabc123 4y ago
        With a history tape calculator, you can easily and intuitively juggle 5 or 6 different numbers --- not just 2.
        brewdad 4y ago
        So what history tape calculator do you use on iOS?
        jqpabc123 4y ago
        None --- I don't use iOS. Inferior software support is one of the reasons why. These are readily available on other platforms. The Android default calculator supports this by simply pulling the display down to reveal "history". And there are a bunch of other apps with even more advanced features and functionality. Personally, I use an RPN calculator where I have a whole stack to work with --- not just 2 numbers.
- zem 4y ago
  absolutely
colinmhayes 4y ago
The base calculator on iPhone is pretty horrible in my experience, but I guess I'm not the target audience. I've really enjoyed eduCalc Classic. It has graphing functionality plus a "guess the function" game based off graph + table which has become my go to plane activity. The unit converter is super useful too.
- mejutoco 4y ago
  What is even worse is the ipad has no default calculator (or weather app). I was so surprised it did not exist I ported the iphone app as a pwa using Typescript and wrote about it here. https://mejuto.co/the-ipad-did-not-have-a-calculator-so-i-ported-the-ios-calculator/ https://mejuto.co/the-ipad-did-not-have-a-calculator-so-i-po...
  - HellsMaddy 4y ago
    iPad finally [0] has a default weather app in iPadOS 16, but still no calculator. [0]: https://www.theverge.com/2022/6/6/23156804/apple-weather-app-ipad-ipados-16-wwdc-2022 https://www.theverge.com/2022/6/6/23156804/apple-weather-app...
    - vxNsr 4y ago
      What’s even harder to understand is why there isn’t a good 3rd party iPad calculator app. This doesn’t feel like a difficult problem to solve, and yet here we without an intuitive, good looking calculator for the iPad.
      - RockRobotRock 4y ago
        just wanted to link Craig's response to why there isnt a calculator for iPad: https://youtu.be/Q2aaCDNjWEg?t=900 https://youtu.be/Q2aaCDNjWEg?t=900
        vxNsr 4y ago
        Yea yea yea. That’s why I said 3rd party. I know they long ago decided not to make an app and have given up on the idea. But you’d think someone would step up in their place and make something useful.
tobr 4y ago
What a wonderful kludge. People can’t imagine that they would be able to go back and edit, or even see, the history of their calculations, so putting two calculators side by side seems like a brilliant idea. It’s like if a new word processor consisted of two faithfully recreated typewriters, with a special button to send the most recently typed word back and forth between them.
- vxNsr 4y ago
  The issue is that the default Calc doesn’t let you see history and nearly every single 3rd party calc doesn’t follow iOS design principles, just doesn’t look very good, and are often inexplicably slow.
  - brimstedt 4y ago
    Why does a calculator need to look good?
    - vxNsr 4y ago
      Why does anything need to look good?
      - MonkeyClub 4y ago
        Because we deserve it. /s
- jldugger 4y ago
  Indeed, this is, like, a solved problem on every other platform! Apple instead designs their apps after tech from the 80s[1] and is now stuck there for life. [1]: https://www.creativebloq.com/design/iconic-calculator-inspired-iphone-app-re-released-5132723 https://www.creativebloq.com/design/iconic-calculator-inspir...
  - pwinnski 4y ago
    Indeed, it's a solved problem on iOS too! This story isn't about someone releasing a new app into a desolate marketplace without any calculator apps (and hey, turn that iOS default calculator sideways for some fun), it's a human interest story about someone releasing a new app into an already-crowded market with a slightly new twist, and finding success there.
apike 4y ago
> For example, if a user calculates "89 x 15 = 1335" on one calculator and taps the arrow key, the result "1335" will be displayed on the other calculator, allowing the user to continue a problem while the previous equations are still shown on the screen. This makes it easy to notice errors. While the UI is very different, the key benefit described here reminds me a lot of Soulver: https://soulver.app/ https://soulver.app/ I love Soulver for how quickly it lets you throw together quick guesstimates and sanity checks. The ability to incorporate previous results by reference and update those on the fly greatly improves the clarity and my confidence in my experience.
- m_eiman 4y ago
  I like Soulver, and also Tydlig: http://tydligapp.com/ http://tydligapp.com/
  - Y-bar 4y ago
    I love Tydlig! But have not seen a single update in many years now, and there are a few rough edges in iOS 15 I wish they had fixed. Is it abandoned?
- nordicio 4y ago
  Shameless plug for my app Kalkyl which I just released 3.0 of that adds functionality like this + collaborative editing and sharing, dimensional analysis, arbitrarily complex unit conversions, and possibility to define your own functions. https://apps.apple.com/se/app/kalkyl/id519933025?l=en https://apps.apple.com/se/app/kalkyl/id519933025?l=en
- shepherdjerred 4y ago
  Oh this looks great! I use Numi but it is a bit too simple. https://github.com/nikolaeu/Numi https://github.com/nikolaeu/Numi
- nick0garvey 4y ago
  I make heavy use of Soulver. Really quick way to do some quick calculations with good unit conversion. e.g. I can write hosts = 100; disk_space_used = 10MiB/s * hosts * 3 days as TiB And it works as expected. Powerful tool when doing capacity planning or other load calculations.
zie 4y ago
Neat, but a log of transactions would do the same thing, easier wouldn't it? RPN calculators tend to do this nicely.
- fortran77 4y ago
  Yes, but not as fast and intuitive, especially for people of a certain age who are used to working with a desk calculator nearby at all times.
- pshc 4y ago
  This two-calculator setup has the advantage of being intuitive to anyone despite having only two storage slots. Or rather because it has only two storage slots and they’re always visible in fixed places.
  - zie 4y ago
    Fair enough. I'll just stick to my history keeping calculators. :)
dm319 4y ago
Some similarities with RPN, except instead of two calculators working on two registers side by side, it's one calculator working on the bottom of several registers. Both allow you to do complex interim calculations that can be hard to plan out on algebraic alone.
paxys 4y ago
What's interesting is that saving the results of a previous operation to memory and recalling/clearing them (M/MR/MC buttons) has been standard in calculators since the very beginning. It just has the most non-obvious user experience in the world so most people don't even know about the feature.
- dr_dshiv 4y ago
  A light dawns, thank you.
- kube-system 4y ago
  Being able to visually see the number would be helpful. I haven't seen any that visually show what is stored in memory until you recall it. It would be pretty neat if pocket calculators had a second line for that feature.
  - tyingq 4y ago
    Yeah, the current Windows calculator has a tab that shows the memory, and I do use it. It would be nice on a physical calculator.
- pleb_nz 4y ago
  It can also be confusing and hard to use for a lot of people and once it's failed for a user once or twice, they'll likely give up with it. I have even succumbed to copy n paste as the cognitive load is less and safer. This however is very obvious and I think it's a great idea. If I had iOS I think I would install it.
- hn_throwaway_99 4y ago
  It's not just that people don't know about the feature. I'd argue having the side-by-side calculator views is fundamentally different (and much better) than just having a memory-store/memory-recall button. E.g. in this app, you get to see the full equations that went into a particular set of calculations as you go back and forth.
  - 4y ago
syntheticnature 4y ago
"If I had asked people what they wanted, they would have said faster horses." -- attributed, apparently wrongly, to Henry Ford. Those of us who know RPN and other options are likely to squirm at this app, but in this case the "faster horse" approach seems to be easy for people to pick up and understand.
- klipt 4y ago
  Horses are self driving so if you count the billions invested into self driving cars, I guess we really do want faster horses ;-)
  - KaoruAoiShiho 4y ago
    Not aware of any horse from which I can watch a movie on and not have to control at all.
    - wikfwikf 4y ago
      There are plenty of accounts of drunk Victorian men letting their horses lead themselves home.
    - NoGravitas 4y ago
      Depends if the horse knows where it's going. If it's going home, no problem.
gkfasdfasdf 4y ago
Neat feature, IIRC Apple does not have a default calculator app because they can't make one that sets it apart from other apps as is the 'Apple way'. Maybe they should just adopt this one.
- sbierwagen 4y ago
  Both iOS and MacOS have default calculator apps. They should look familiar: he copied the interface design exactly for his app.
- deleted 4y ago
  [deleted]
- kevinslashslash 4y ago
  It's just the iPad doesn't have a default calculator app https://www.howtogeek.com/820792/where-is-the-calculator-app-on-ipad/ https://www.howtogeek.com/820792/where-is-the-calculator-app...
ape4 4y ago
I first thought it was going to show results in hex and decimal at the same time.
- spc476 4y ago
  I wrote my own desktop programming calculator that shows signed and unsigned decimal, octal, hexadecimal and binary at the same time. It also allows you to select 8-bit, 16-bit, 32-bit or 64-bit calculations, and do either signed extend (for converting from a lower bit to higher bit legnth) or zero extend. No floating point results though. It was a fun project to work on.
furyofantares 4y ago
This seems pretty smart to me. I think it's being dumped on because it's a "dumb" solution to something that is a non-problem for all of us here, which is probably why I've never seen this solution before. None of us would think of it. But I think it's true that while most everyone knows how to use the most basic functions of a calculator, most people don't get any further than that, and this allows them to.
- codeulike 4y ago
  I have a degree in Mathematics and I can never remember what C and CE buttons on a calculcator are supposed to do. If you only use them occasionally and in a hurry most calculator apps are frustratingly unfriendly.
- whywhywhywhy 4y ago
  Although Soulver like apps are definitely a better solution. I actually think this 2 calculator app is kinda genius in the sense that people over 60 can instantly understand it and fit it into their workflow.
mikewarot 4y ago
This UI has a better impedance match to the way he, and many people who used desk calculators, think. It's quite elegant.
- PTOB 4y ago
  That's a great way to use that term. I like it very much.
- jiveturkey 4y ago
  I find it to be very japanese. elegance expressed in such a simple form. blindingly obvious ... now. so hard to arrive at this design choice. i love this. it's poetic.
yieldcrv 4y ago
Wow, I need to look for more contrived but accepted user experiences to fix!
wishfish 4y ago
That's a brilliant & simple idea. I love it. Makes me wonder if anyone's made a small screen spreadsheet? Seems like that would be the obvious next step. Something like a default of 3x4 or 4x4 cells. Would have most of the basic spreadsheet functionality, and maybe simple graphs to show comparisons. Interface designed for touch on a six inch screen.
- giarc 4y ago
  I've always wanted a browser extension (or similar) that opens a small 10x10 spreadsheet so I can quickly do some calculations. For example, if you are shopping online and have various options that all have different shipping costs etc. It would be nice to do a quick breakdown of costs without having to open Excel.
  - wolpoli 4y ago
    That would be a great idea! That's the perfect use for the "spreadsheet implemented in Browser" submissions we have seen over the years!
  - wishfish 4y ago
    It's a little surprising Google hasn't done this already. A small (maybe inline, maybe floating) popup that gives you a little grid. Would autosave to Sheets. That would be perfect. Anyways, that's a great idea you have. I never knew I wanted this, but now I want it very badly.
    - aj7 4y ago
      If you paste an expression into the search box… Try it with (66/6)^2/2
    - themarkn 4y ago
      It’s pretty fast to pop open a new tab and visit sheets.new, I do this a lot but not everybody knows about it (and the rest of the .new TLD) The in-line floating thing is not too attractive to me. But yeah, new window, sheets.new, split screen, you’re spreadsheeting before you know it.
1970-01-01 4y ago
So he took a niche device and made it an App. Smart! https://www.casio.com/us/basic-calculators/product.DV-220/ https://www.casio.com/us/basic-calculators/product.DV-220/
- pvillano 4y ago
  That's a fun idea: remaking good products that no longer meet the volumes for mass production, but still have enthusiasts who could finance a limited run. Like the new Commodore 64
- jiveturkey 4y ago
  yo dawg, i heard you like calculators ...
anotheryou 4y ago
I can highly recommend https://bbodi.github.io/notecalc3/notecalc https://bbodi.github.io/notecalc3/notecalc Web based Soulver-like calculator that is a bit more like scripting. totally different, but wonderful.
- insane_dreamer 4y ago
  Nice. Gonna bookmark this one.
- haint_ 4y ago
  This is great, but I can't seem to copy the result. Is it just me?
  - anotheryou 4y ago
    oh weird, not just you. In the export preview you can, hope there is a better way though.
  - anotheryou 4y ago
    found it out: hit ctrl+c in any line (without any character selection) to copy the result.
    - haint_ 4y ago
      Thank you, but I wish we could manually select it and copy the desired part (for example when converting days to seconds I'm only concern about the actual seconds, not the "seconds" suffix)
quartz 4y ago
The best feature on the Mac's built in calculator is the paper tape (⌘+t) which I stumbled on ages ago while accidentally having the calculator open and trying to open a new tab in my browser. I always leave it open now and it has saved me countless times. Really with the iOS version had this feature built in as well.
- faxmeyourcode 4y ago
  Woah, thanks! This is an awesome feature I never would have found on my own
- hn_throwaway_99 4y ago
  Thanks for the tip! Interestingly, I found it weird how the app handles order-of-operations. That is, if you type 1 + 2 / 2, the answer shows up as 2 and the paper tape shows 1 + 2 / 2 = 2 However, if you type 1 + 2 = / 2 (that is, you type equals after the 1 + 2, which will show 3 on the screen, before typing the / 2 part), the last line of the paper type shows 1 + 2 / 2 = 1.5 They need to add some parentheses in there.
  - contingencies 4y ago
    It's the accepted order of operation in maths that you resolve multiplication and division before addition and subtraction. While the single-value-view of a calculator removes visual context, if you are banging out multi-step calculations as a power user not having the standard order of operations would be odd. The workaround, as you say, is to just press enter (equals) after each required subtotal. This is pretty semantically clear, that is - if you consider a traditional keyboard to even be a thing that young people are familiar with - and that is getting arguable! Key corollary issues to the single-value-view nature of computer calculators are that they pull a lot of (now obtuse) cultural context from physical calculators plus regular mathematical context, none of which is obvious to occasional computer calculator software users. It's probably high time this stuff was rejigged. Thanks for the paper tape tip!
    - 5fOleL5Eo2So8qi 4y ago
shabbatt 4y ago
LordHeini 4y ago
Not sure if this app can do stuff like cross multiplication or run the same operations on both calculators. But this app reminded of something similar. There is an old school double mechanical pinwheel calculator: https://www.youtube.com/watch?v=qnlzKCFP0sU https://www.youtube.com/watch?v=qnlzKCFP0sU It was probably mostly used for coordinate calculations. I own one of those brunsvigas (the single stage one) and it is fascinating what these things can do. A mechanical calculator with enough didits can solve cross multiplication rather easily.
dpb1 4y ago
Some of the strong points of this calculator is the main thing I use in RPN calculators with stacks. It's so helpful for me to duplicate a value and then operate on that, and be able to throw it away if I mess up, sanity check from where I started at intermediate calculations, etc. it's not identical, but many points others are mentioning in this thread are what I value from an RPN stack based calculator. BTW, for anyone who is comfortable with RPNs, MacOS added the mode to their built-in calculator recently-ish. it's not terrible either. I've switched to it for my default experience. (even though nothing beats the HP 48g, as it's what I'm the most familiar with). Also, on the article, really cool that someone added this on mobile. I love hearing about devs developing something that fills a niche and does so well. I feel like I'm out of ideas most days. Good for her!
- deepspace 4y ago
  I was thinking the same thing while reading the article. I have been using RPN calculators for 40 years, and it has become second nature to manipulate the stack to have two calculations going at the same time, and then merging them, if needed.
  - bollu 4y ago
    What's the RPN based calculator you use on your terminal? I'd love to learn!
    - self 4y ago
      dc, perhaps.
    - dr-neptune 4y ago
      Not sure what the parent uses, but emacs has calc, which is a RPN calculator with lots of features (including history and intermediate results) and can be used in the terminal
    - deepspace 4y ago
      To be honest, I mostly use a physical calculator (Swissmicros DM41L, which is an HP41CX clone). Second choice is the i41CX+ app on my phone. The HP41 keyboard and operational patterns were etched into my brain at university, since my first engineering calculator was an HP41C. I have used rpncalc and T_REX (https://isene.org/2021/02/T-REX.html https://isene.org/2021/02/T-REX.html) in the terminal, dc or gforth in a pinch.
asimpletune 4y ago
Improving upon the design of a calculator app is incredibly difficult. And before people complain that it's not improved, yes it is. For most people, this is way better. Congrats to him, he's living the dream. Building software that does a job, and then getting paid for that software. I just hope he doesn't suffer too many copycat apps.
- FrasiertheLion 4y ago
  This article made me realise why I use a python shell over a calculator app. It's nice to refer back to my previous computations and results. Several people here mention RPN; I work in tech, definitely understand stacks and get that I would be able to view my previous computations. Yet it's not something I took the time to discover, there were always other ways. I've always believed that there is still a lot of low-hanging fruit left in crafting user friendly experiences for consumer facing applications. Who would have guessed this would be the case even in the design space of something as fundamental as calculators! ~20k paid users seems surprisingly large. But I'm not plugged into the app dev scene, so perhaps this isn't unusual.
- gustavorg 4y ago
  > I just hope he doesn't suffer too many copycat apps. There were 2k clones of flappy bird within a month of its release. By now there must be at least a dozen programmers copying this idea (Twin-Calc) for other platforms, myself included.
jhallenworld 4y ago
My daughter is struggling with this problem: on TI-84s, "(-) 3 x^2 Enter" gives -9. Personally, I think that if you have a dedicated negation operator it should have a higher precedence than power, but at the very least the calculator could highlight what it's doing. "Hypercalc" the Android app does it, but TI-84 is the standard..
- macintux 4y ago
  Obligatory but futile plug for HP RPN calculators.
  - cfraenkel 4y ago
    Seconded. But I'm afraid RPN is an endangered species. Who's learning it anymore?
    - kccqzy 4y ago
      Probably every computer science student learns it in order to implement something useful after learning about the stack.
- Georgelemental 4y ago
  > a dedicated negation operator it should have a higher precedence than power I prefer the traditional precedence; it ensures - 3 ^ 2 = 0 - 3 ^ 2
  - jhallenworld 4y ago
    I understand the argument, I just wish that the most standard school calculator would highlight somehow what it's doing Another one is "2 ^ 1 / 2 Enter". Some calculators give 1, newer ones give sqrt(2).
- weberer 4y ago
  I'm not sure what the parenthesis around the negative sign is supposed to accomplish. Generally you put it around two or more operators.
ilos 4y ago
5fOleL5Eo2So8qi 4y ago
The hard part of writing a calculator app is not parsing `0.1` versus `.1`. That's trivial. The hard part of writing a calculator app is getting precise answers instead of floating-point answers, and given that he thinks the hard part is parsing `.1`, it probably gets it wrong.
- kccqzy 4y ago
  Solved by https://www.hboehm.info/new_crcalc/CRCalc.html https://www.hboehm.info/new_crcalc/CRCalc.html Also, this is in the Android stock calculator so lifting the code over is easy. See also https://dl.acm.org/doi/10.1145/2911981 https://dl.acm.org/doi/10.1145/2911981
- outworlder 4y ago
  That's a really large cognitive leap from such a small amount of data. Have you considered that they may not be using floating point numbers at all? They might be using arbitrary precision arithmetic. That was probably implemented by a library. So not as much effort as you would think.
xxr 4y ago
I haven't used this app, but something that makes me smile is that the paid version is only 563KB (the paid version is 4.6MB, and I suppose it's pleasant that the ad SDKs are "only" 4 megs). After seeing every major app take up 100MB+ for years, I had just assumed that there was some kind of static packaging inherent to all iOS apps that jacked the deliverable size up so high. I don't know whether Ueda was deliberately trying to get it as small as possible, or if his design is so elegant that it just naturally led to such a tiny artifact. Either way, as long as the 3.5" floppy is still in its sunset period[0], I suppose it's nice that there's modern software that will still fit on it. [0]https://www.bbc.com/news/world-asia-62749310 https://www.bbc.com/news/world-asia-62749310
- auggierose 4y ago
  If it is an app built in Swift, then iOS and macOS ship already with all of its runtime libraries, so the app itself can be very small.
- Someone 4y ago
  > there was some kind of static packaging inherent to all iOS apps There was for apps using Swift. Before the Swift ABI was frozen, iOS apps using Swift had to statically link the Swift standard library. Nowadays, iOS provides it as a dynamic library. (and having a stable ABI is quite an accomplishment for a language like Swift. See https://faultlore.com/blah/swift-abi/ https://faultlore.com/blah/swift-abi/)
  - saagarjha 4y ago
    The Swift libraries are not all that large, perhaps a dozen MB or so.
- postalrat 4y ago
  The web app version would probably be 1/10th of that.
  - miniBill 4y ago
    I mean... it depends what you want to support. My web calculator [fully client side] is 370kb of JS. It has features that this doesn't have (3d rendering, solving equations), but doesn't have code that this needs (mostly, the keyboard)...
ctrlc-root 4y ago
If you're looking for something similar on the desktop I use SpeedCrunch to address the same need. You can chain calculations and refer back to previous entries while seeing your history. https://heldercorreia.bitbucket.io/speedcrunch/ https://heldercorreia.bitbucket.io/speedcrunch/
- mjcohen 4y ago
  Can't open it on MacOS Monterey because owner cannot be verified.
jjnoakes 4y ago
It'd be cool to take this a step further - allow for a tree-like setup of as many calculators as you want. Each number in one calculator's equation could be expanded out into a separate calculator where the number was computed, etc.
- pyinstallwoes 4y ago
  Memoize and precompute every calculation over a merkle tree distributed on a decentralized network using content addressable memory hashed to every calculation as the hash you say? Yeah love it.
  - jjnoakes 4y ago
    Did you reply to the right comment? I'm not sure I follow...
supernova87a 4y ago
> ...Ueda recalled, "I thought it'd be easy, but it was unexpectedly hard." ... For example, while there are users who input 0.5 by tapping "0," the decimal point, and then "5," there are also users who only input the decimal point and "5," while omitting the "0." He said, "There were around 100 types of these sort of conditions, and it was a lot of work to solve them." I wonder what other kinds of non-trivial calculator behaviors he had to rediscover from scratch?
- thrdbndndn 4y ago
  About this specific case: I also never knew using ".5" to mean "0.5" is a thing, until I lived in the US. Not sure if it's a US thing or Western world thing, my country (not Japan, but also in East Asia) just doesn't use it.
  - Ferrotin 4y ago
    Probably your calculators all support it.
    - thrdbndndn 4y ago
      Yeah they do, just didn't know this notation (convention?).
      - Ferrotin 4y ago
        Oddly, I don’t think I’ve ever noticed the zero being omitted except casually or to save space in a table, in English. I would expect ordinary writing to include the zero.
  - NavinF 4y ago
    That's surprising. People don't say stuff like "try setting power level to point three"? Do they use a different word for the decimal separator?
    - 4y ago
indigodaddy 4y ago
Simple and effective.
vertis 4y ago
I quite like Numi[0] (Mac), also available as part of SetApp[1] [0]:https://numi.app/ https://numi.app/ [1]: https://setapp.com/apps/numi https://setapp.com/apps/numi
layer8 4y ago
This would almost be unnecessary if iOS allowed two instances of the same app to be opened (and displayed in split view). I’m saying “almost” because the integrated app is of course easier for non power users.
injidup 4y ago
A spreadsheet with two cells only. Take that bloatware excel!
- jiveturkey 4y ago
  underrated comment
aj7 4y ago
A huge strength of the original HP9100A programmable calculator, http://archive.computerhistory.org/resources/text/HP/HP.9100A.1968.102646164.pdf http://archive.computerhistory.org/resources/text/HP/HP.9100..., was that ALL 3 rpn stack registers were visible AT ONCE ON THE CRT. So he has resurrected the original blank slate engineer’s intent; Osborne realized that people would be uncomfortable “knowing” stuff was in hidden registers, as apparently a great deal of non-technical people are today, 52 years later.
- Severian 4y ago
  Wow, that's a good looking brochure. I always loved that style of illustration.
WalterBright 4y ago
I'm actually kind of shocked. The calculator apps emulate a calculator, but they don't take any advantage of having the phone screen. A proper calculator app would allow you to type 1.6*2/3 and display the equation on the screen, not just the 3.
- newtritious 4y ago
  This one does: https://jacobdoescode.com/technicalc https://jacobdoescode.com/technicalc
  - WalterBright 4y ago
    That looks pretty sweet!
    - WalterBright 4y ago
      dang, IOS 13 or later.
icedistilled 4y ago
Why don't calculator apps at the very least display the current calculation like the casio FX-95? The current options of basic or scientific for mac/ios would be 100x better. The ticker tape only partially solves it. FX 95: https://www.casio.com/intl/scientific-calculators/product.FX-95MS/ https://www.casio.com/intl/scientific-calculators/product.FX...
qwezxcrty 4y ago
I don't see how this works better than any scientific calculator that shows history. Also don't understand why he put two sets of keyboards, to me it just doesn't make sense. Marginally related: if you are looking for a non-sucking calculator app on desktop or mobile, try an emulator of a (modern or retro, at your choice) HP or TI graphical calculator. My personal favorite is the emulator of HP Prime.
- codeulike 4y ago
  Its immediately intuitive without having to think about it. Its two calculators. Its magnificent.
- NavinF 4y ago
  Umm of course history is superior. So are named variables. You and me are not the target audience. Ever noticed how normal people hit both C and CE several times on physical calculators because it's not obvious what those buttons do? That's the target audience.
imhoguy 4y ago
Is it only me who sees a humble man enjoying his own ikigai[0] in simple but challenging creation? The photo says it all. [0]https://en.wikipedia.org/wiki/Ikigai https://en.wikipedia.org/wiki/Ikigai
chongli 4y ago
It’s interesting but the duplicate sets of buttons are a big waste of space. My favourite free calculator app is Desmos Scientific (by the makers of the graphing calculator) [1]. This app gives you as many entry lines as you like and they all remain live. You can also define variables and functions in one line and use them in another. In effect, it’s like a single column from a spreadsheet. [1] https://apps.apple.com/ca/app/desmos-scientific-calculator/id1235292051 https://apps.apple.com/ca/app/desmos-scientific-calculator/i...
aasasd 4y ago
Total Commander and Ghost Commander on Android solve the problem of two panels in the portrait orientation by displaying one of them and having a button to switch to the other one. However, seeing as some of the success of this calculator app is probably attributed to the ‘memory’ function being non-obvious to people, I'd guess that a hidden calculator might also put some off.
gfodor 4y ago
If you liked this app, stay tuned - I am working on a 3-calculator app that increases the utility of this app by up to 50%.
- misterprime 4y ago
  LOL, can you make it dynamically have as many calculators as there are cores on the CPU and guarantee that each calculator only uses a single unique core for its own calculations?
  - BowBun 4y ago
    I don't think you need to limit the number of calculators to the number of cores. You can just store the history/results somewhere on disk or in memory. Which core doing the work when you press '=' doesn't really matter in this case unless you're load-testing this calculator.
  - megablast 4y ago
    I mean, why?? Do you think the calculator is a heavy CPU view??? You still only use one at a time anyway. And yes, you could easily have 10,000 calculators or more.
    - misterprime 4y ago
      Thanks, sorry. It was just a silly response to a silly comment.
- insane_dreamer 4y ago
  but does it run on the GPU?
  - TheOtherHobbes 4y ago
    The calculations are the output of an ML solver trained on a data set generated by corporate accountants.
TheSpiceIsLife 4y ago
Any software calculator that has a tape feature works well for me, I think the built in windows calc app does. I've been using CalcTape for a few years now, it's a calculator and notepad in one. https://www.schoettler-software.com/en/calctape/windows https://www.schoettler-software.com/en/calctape/windows I appreciate the simplicity of the side by side calculator app though.
savrajsingh 4y ago
This is the perfect example of how we, as devs, way overthink what people actually want / are comfortable with.
fyloraspit 4y ago
This is basically the same reason I default to speedcrunch for my calculator app. It has a nice visible and interactive history of calculations.
- iisan7 4y ago
  Currently a big fan of https://clcalc.net/ https://clcalc.net/. I went through calculator withdrawal after I left Windows XP and the great (for its time) Powertoy Calculator at https://www.rarst.net/software/powertoy-calculator/ https://www.rarst.net/software/powertoy-calculator/. I wanted to like speedcrunch but I abandoned it, because I've found that it takes longer to load (4-5 seconds or more) than I need to have it open (1-2 seconds).
  - haint_ 4y ago
    Thanks, it works great, but I found it better to have 2 sides: expressions on the left and results on the right. Maybe I'm already too familiar with Numi, lol.
FilterSweep 4y ago
> It is also possible to perform different computations on each calculator. This function comes in handy when the user wants to compare prices to determine which store product is cheaper by the gram, for example. This adds another use-case outside of the M functions on a standard calc :)
cobaltoxide 4y ago
Personally I find it embarrassing that we use a device with gigabytes of RAM and millions of pixels to emulate a 19-button device from half a century ago.
- pvillano 4y ago
  It's probably hard to come up with a better interface. A pocket calculator can be operated with very little cognitive load. It's easy to memorize because things don't move and it's easy to discover because ~every action is always visible. It's also good enough. Most people don't need more than a pocket calculator. Sometimes I use WolframAlpha, very modern, but I type my query on a keyboard whose design predates the calculator (QUERTY in <1873 vs "10-key" calculator in 1902)
  - cobaltoxide 4y ago
    I like to use a REPL (like MATLAB or Python) where I can enter expressions with a real keyboard instead of hunting and pecking the skeumorphic calculator GUI. This also allows me to see the history of my calculations without resorting to the weird mirrored calculator. Even something like a TI-85 graphing calculator offers this.
- fomine3 4y ago
  Yeah buttons should be rendered with ray tracing and deep learning
Mathmanjetson 4y ago
asimjalis 4y ago
This can also be used for what if scenarios based on an intermediate result.
angry_octet 4y ago
New calculator feature request: export the calculation stream to the clipboard and CSV/excel, same as old paper tape calculators.
DangitBobby 4y ago
I love this! Also, today I learned that you can scroll through your history in the built-in android calculator by swiping down on the number input field!
Ferret7446 4y ago
How odd. I see a lot of discussion about calculators having history and such, but as someone who became acquainted with Emacs's Calc mode at an early age, it seems so strange that calculators with history are a foreign concept to most people.
- MandieD 4y ago
  The vast majority of people outside of Unix-adjacent computing have never heard of, much less used, emacs. More broadly, most people have never used any form of REPL, including the handy PowerShell that has come out of the box with Windows for a good decade now. This app succeeds because the developer has hit upon an interface that better matches normal users' mental models around calculators.
waynesonfire 4y ago
it's also less keystrokes relative to M/MR/MC technique when chaining computation, since, you have two calculators enable concurrency.
ChicagoBoy11 4y ago
What a fantastic example of "make something people want." Kudos to him... and so inspiring!
WiSaGaN 4y ago
This is the innovation that everybody would see how obvious it is once it's out. And yet no one thought about making it for a very long time.
noobermin 4y ago
I think this is why I prefer using the python idle as a calculator. You can assign an expression to a variable, but you can always scan up (assuming your terminal window is tall enough) to see what expression you used to calculate it. People are saying how this is the point of memory on calculators but once you save to M you basically need to remember what's in there. Seeing what you did to calculate whatever is better. In a way then, the python idle is like this but with many calculators side by side.
- bee_rider 4y ago
  Python is fine, although I find that Octave gets me to "doing a calculation" in a couple fewer keypresses.
- Georgelemental 4y ago
  I like qalc (https://github.com/Qalculate/libqalculate https://github.com/Qalculate/libqalculate) as a command-line calculator. It has all the basic repl features, but also excellent units support and other useful math-oriented things.
deleted 4y ago
[deleted]
mrb 4y ago
What I want is a phone app calculator that works like the Python REPL/console. Save ALL previous calculations. Display the last dozen or so. Can scroll through them. Tap on one to recall it, edit one number, recompute. Done. This would beat by far the convenience and usability of this 2-in-1 calculator. I would KILL to have this. In fact, on my laptop, I use the Python REPL as a calculator. I hit Ctrl-T python ENTER. It opens a terminal and I start typing 48*152 ENTER and I see the result. The history of calculations is saved. I can access previous calculations, edit one number and recompute. I see the last 100 lines or so, on one screen. The only one somewhat usable Python REPL on Android is "Pyonic Python 3 interpreter" but it's clumsy to use as a calculator because it uses the standard alphabetic keyboard so you have to keep switching to the special characters layout to type math operators (-+/...) If this ONE detail would be fixed, and with some minor UI polish I believe it could become more popular than the 2-in-1 calculator...
- adriansky 4y ago
  Exactly! I created calculator app with history for this reason. It also allows you to copy and paste from past results. - iOS: https://apps.apple.com/us/app/instant-calculator/id1632328821 https://apps.apple.com/us/app/instant-calculator/id163232882... - Android: https://play.google.com/store/apps/details?id=com.adrianmejia.calculator https://play.google.com/store/apps/details?id=com.adrianmeji...
- Georgelemental 4y ago
  qalc (https://github.com/Qalculate/libqalculate https://github.com/Qalculate/libqalculate) is my command-line calculator of choice. Its killer feature IMO is the units support
  - mrb 4y ago
    Very cool ! For units conversion I use GNU Units. But qalc seems to combine the benefits of both the Python REPL and GNU Units. I just tried the command-line version and noticed it doesn't support recalling the history (UP arrow) and editing calculations. This is unfortunately a deal-breaker :-( Don't have time to submit a patch.
pyinstallwoes 4y ago
Reminds me of a two stack push down automata. Stack programming languages. Forth lang.
jiveturkey 4y ago
it's too bad i can only buy one copy of this app. if only apple would allow the purchase of 2 copies. but the universe might collapse then, having reached its poetic end.
easygenes 4y ago
For me the killer convenience calculator on mobile has been Soulver. The UI is just perfect for making it easy to string together calculations without taking up too much screen real estate. Irritatingly, the Mac app is available still, but it has been pulled from the iOS App Store for a long time, and it’s not on any other platforms. If something like Soulver existed cross platform I would have it installed on everything.
hnjst 4y ago
I'm still completely baffled that we nowadays almost all have in our pocket a device able to run something like https://f-droid.org/en/packages/jp.yhonda/ https://f-droid.org/en/packages/jp.yhonda/.
ycombinete 4y ago
Just bought this for my iPad, which apple inexplicably doesn’t bundle with their calculator app.
chacha21 4y ago
An opportunity to post again my thoughts about software calculators ! https://chachatelier.fr/chalk/article/chalk.html https://chachatelier.fr/chalk/article/chalk.html
- Liquid_Fire 4y ago
  Have you ever tried Qalculate? I don't see it mentioned in your article. It feels like it addresses most of your points for creating Chalk, and it's already cross-platform.
  - chacha21 4y ago
    Most people didn't understand that my goal was not to benchmark all existing calculator apps. It is on purpose that I did not mention all "pretty good" softwares, because I cannot know them all. The article I wrote wants to mention every point that should be adressed (in my opinion) to make a good calculator. Qalculate, like many others, does address some of them. But as far as I know, only Chalk addresses all of them.
tempodox 4y ago
This is such a nice example of how relatively simple ideas can still be of huge utility.
mfbx9da4 4y ago
This epitomizes my passion for coding -- it's the lowest barrier to entry for being an inventor
frou_dh 4y ago
Similar to the 80-something Japanese woman who created an iPhone app relating to a doll festival, that was a big news story a couple of years ago.
adrianomartins 4y ago
Wow, this is some inspiration right here. Never too late! Also, do you have a pain, build a solutions! Congrats to that retired engineer!
- pluijzer 4y ago
  > Never too late! From your comment and some other comments and the way the article is written I gather that the engineers age is seen as something novel. Do people really see 63 as an newsworthy fact? Not trying to troll, I honestly wonder. It is 4 years from retirement in my country and I see many other achievements come from much older people. I just don't see 63 as anything special or old.
  - Sebb767 4y ago
    It's unusual for people in that age group to be good with computers, as they grew up without them (or at least without them being as ubiquitous as in the last few decades). It's also pretty rare to hit such a sweet spot with an app, which makes it somewhat unusual that someone from that age group managed to do so.
mavhc 4y ago
Wait until they try a GUI with windows
runeks 4y ago
> For example, while there are users who input 0.5 by tapping "0," the decimal point, and then "5," there are also users who only input the decimal point and "5," while omitting the "0." The practice of including punctuation inside the quote makes this a somewhat confusing sentence, at least if you’re used to using a comma instead of a period for the decimal point.
effnorwood 4y ago
fennecfoxy 4y ago
Really cool project for a retired engineer to do. Kind of reminds me of the "Notebooks" concept that Jupyter and others use (I dipped my toes in it, not an expert). Would be nice if he could abstract the calculators to a list/hierarchy of calculations performed, then be able to "open" limitless additional calculators as desired and swipe between 'em. Being able to see a hierarchy of calculations and say, go back to a parent one and modify the value or part of the calculation itself and have child ones update would be super cool.
supermatt 4y ago
Fantastic! A great example of a simple product that people want/need.

979 points by CrankyBear 4y ago

Seems like if you allowed swapping out a background set of sub calculators, and provide inter-calculator ops on the front two, you’ve recreated an elegant cross between the RPN and standard calculator models.

PaulHoule 4y ago

"The number of downloads grew at a sluggish pace at first because the app was designed so that just one calculator is displayed on the smartphone's vertical screen mode, while two are shown only when the screen is rotated on its side. So, many users only thought it was a regular calculator."

jqpabc123 4y ago

So is this significantly better than just using store and recall?

flowerbreeze 4y ago
In my opinion it is, because I don't need to recall what I recall.
- jqpabc123 4y ago
  When I need to recall what I recall, I just hit [MR].
  - hn_throwaway_99 4y ago
    Which causes you to then lose what you have typed in the screen already. TBH, these semi-snarky "How is this any different from MS/MR?" responses are like "Why should a CPU ever need more than 2 registers?" to me.
    - tremon 4y ago
      But then, why should my phone screen be limited to only 2 calculators?
      - jqpabc123 4y ago
        Instead of more calculators, all you really need is just better design. See above.
    - jqpabc123 4y ago
      Which causes you to then lose what you have typed in the screen already. Then hit [MX] instead. Problem solved with 1 button instead of a whole extra calculator. "Why should a CPU ever need more than 2 registers?" The question in this case is "Why should a calculator only have 2 registers". This approach doesn't scale beyond 2 numbers? Personally, I prefer RPN where I have a whole stack to work with.
      - hn_throwaway_99 4y ago
        What is the [MX] button? I don't think I've ever seen that on a calculator. TBH, though, this is still kind of like arguing that people should never need GUIs because you can do everything on the command line. There is a pretty obvious, fundamental difference being able to see everything on the screen at the same time, vs having to remember what you stored in memory (and what calculations went into it). As for RPN, while I agree most people are never taught RPN.
        jqpabc123 4y ago
        [MX] = Memory Exchange --- Swap display and memory A better, more intuitive solution than any of the above with available screen real estate is a history tape of prior resultants created automatically. Multiple prior resultants (not just 2) always available to view --- no action required. To recall a number from the tape into the active accumulator for further manipulation, simply click the number. To remove a number from the tape, click and drag right or left. To reorder, click and drag up or down.
naikrovek 4y ago
in terms of ease of use and visibility yes I would say this is more than significantly better.
criddell 4y ago
It’s only $3. How much better does it need to be to be worth $3?
- jqpabc123 4y ago
  What happens if I am working with 3 or 4 different values? This duplicate calculator method doesn't scale too well. A history tape is a better option --- just as intuitative but more capable/flexible.
  - criddell 4y ago
    Are you looking for people to tell you this is what you should be using? If it doesn't work for you, then use something else.
  - outworlder 4y ago
    Then you start approaching spreadsheet territory.
    - jqpabc123 4y ago
      With a history tape calculator, you can easily and intuitively juggle 5 or 6 different numbers --- not just 2.
      - brewdad 4y ago
        So what history tape calculator do you use on iOS?
        jqpabc123 4y ago
        None --- I don't use iOS. Inferior software support is one of the reasons why. These are readily available on other platforms. The Android default calculator supports this by simply pulling the display down to reveal "history". And there are a bunch of other apps with even more advanced features and functionality. Personally, I use an RPN calculator where I have a whole stack to work with --- not just 2 numbers.
zem 4y ago
absolutely

colinmhayes 4y ago

The base calculator on iPhone is pretty horrible in my experience, but I guess I'm not the target audience. I've really enjoyed eduCalc Classic. It has graphing functionality plus a "guess the function" game based off graph + table which has become my go to plane activity. The unit converter is super useful too.

mejutoco 4y ago
What is even worse is the ipad has no default calculator (or weather app). I was so surprised it did not exist I ported the iphone app as a pwa using Typescript and wrote about it here. https://mejuto.co/the-ipad-did-not-have-a-calculator-so-i-ported-the-ios-calculator/ https://mejuto.co/the-ipad-did-not-have-a-calculator-so-i-po...
- HellsMaddy 4y ago
  iPad finally [0] has a default weather app in iPadOS 16, but still no calculator. [0]: https://www.theverge.com/2022/6/6/23156804/apple-weather-app-ipad-ipados-16-wwdc-2022 https://www.theverge.com/2022/6/6/23156804/apple-weather-app...
  - vxNsr 4y ago
    What’s even harder to understand is why there isn’t a good 3rd party iPad calculator app. This doesn’t feel like a difficult problem to solve, and yet here we without an intuitive, good looking calculator for the iPad.
    - RockRobotRock 4y ago
      just wanted to link Craig's response to why there isnt a calculator for iPad: https://youtu.be/Q2aaCDNjWEg?t=900 https://youtu.be/Q2aaCDNjWEg?t=900
      - vxNsr 4y ago
        Yea yea yea. That’s why I said 3rd party. I know they long ago decided not to make an app and have given up on the idea. But you’d think someone would step up in their place and make something useful.

tobr 4y ago

What a wonderful kludge. People can’t imagine that they would be able to go back and edit, or even see, the history of their calculations, so putting two calculators side by side seems like a brilliant idea. It’s like if a new word processor consisted of two faithfully recreated typewriters, with a special button to send the most recently typed word back and forth between them.

vxNsr 4y ago
The issue is that the default Calc doesn’t let you see history and nearly every single 3rd party calc doesn’t follow iOS design principles, just doesn’t look very good, and are often inexplicably slow.
- brimstedt 4y ago
  Why does a calculator need to look good?
  - vxNsr 4y ago
    Why does anything need to look good?
    - MonkeyClub 4y ago
      Because we deserve it. /s
jldugger 4y ago
Indeed, this is, like, a solved problem on every other platform! Apple instead designs their apps after tech from the 80s[1] and is now stuck there for life. [1]: https://www.creativebloq.com/design/iconic-calculator-inspired-iphone-app-re-released-5132723 https://www.creativebloq.com/design/iconic-calculator-inspir...
- pwinnski 4y ago
  Indeed, it's a solved problem on iOS too! This story isn't about someone releasing a new app into a desolate marketplace without any calculator apps (and hey, turn that iOS default calculator sideways for some fun), it's a human interest story about someone releasing a new app into an already-crowded market with a slightly new twist, and finding success there.

apike 4y ago

> For example, if a user calculates "89 x 15 = 1335" on one calculator and taps the arrow key, the result "1335" will be displayed on the other calculator, allowing the user to continue a problem while the previous equations are still shown on the screen. This makes it easy to notice errors. While the UI is very different, the key benefit described here reminds me a lot of Soulver: https://soulver.app/ https://soulver.app/ I love Soulver for how quickly it lets you throw together quick guesstimates and sanity checks. The ability to incorporate previous results by reference and update those on the fly greatly improves the clarity and my confidence in my experience.

m_eiman 4y ago
I like Soulver, and also Tydlig: http://tydligapp.com/ http://tydligapp.com/
- Y-bar 4y ago
  I love Tydlig! But have not seen a single update in many years now, and there are a few rough edges in iOS 15 I wish they had fixed. Is it abandoned?
nordicio 4y ago
Shameless plug for my app Kalkyl which I just released 3.0 of that adds functionality like this + collaborative editing and sharing, dimensional analysis, arbitrarily complex unit conversions, and possibility to define your own functions. https://apps.apple.com/se/app/kalkyl/id519933025?l=en https://apps.apple.com/se/app/kalkyl/id519933025?l=en
shepherdjerred 4y ago
Oh this looks great! I use Numi but it is a bit too simple. https://github.com/nikolaeu/Numi https://github.com/nikolaeu/Numi
nick0garvey 4y ago
I make heavy use of Soulver. Really quick way to do some quick calculations with good unit conversion. e.g. I can write hosts = 100; disk_space_used = 10MiB/s * hosts * 3 days as TiB And it works as expected. Powerful tool when doing capacity planning or other load calculations.

zie 4y ago

Neat, but a log of transactions would do the same thing, easier wouldn't it? RPN calculators tend to do this nicely.

fortran77 4y ago
Yes, but not as fast and intuitive, especially for people of a certain age who are used to working with a desk calculator nearby at all times.
pshc 4y ago
This two-calculator setup has the advantage of being intuitive to anyone despite having only two storage slots. Or rather because it has only two storage slots and they’re always visible in fixed places.
- zie 4y ago
  Fair enough. I'll just stick to my history keeping calculators. :)

dm319 4y ago

Some similarities with RPN, except instead of two calculators working on two registers side by side, it's one calculator working on the bottom of several registers. Both allow you to do complex interim calculations that can be hard to plan out on algebraic alone.

paxys 4y ago

What's interesting is that saving the results of a previous operation to memory and recalling/clearing them (M/MR/MC buttons) has been standard in calculators since the very beginning. It just has the most non-obvious user experience in the world so most people don't even know about the feature.

dr_dshiv 4y ago
A light dawns, thank you.
kube-system 4y ago
Being able to visually see the number would be helpful. I haven't seen any that visually show what is stored in memory until you recall it. It would be pretty neat if pocket calculators had a second line for that feature.
- tyingq 4y ago
  Yeah, the current Windows calculator has a tab that shows the memory, and I do use it. It would be nice on a physical calculator.
pleb_nz 4y ago
It can also be confusing and hard to use for a lot of people and once it's failed for a user once or twice, they'll likely give up with it. I have even succumbed to copy n paste as the cognitive load is less and safer. This however is very obvious and I think it's a great idea. If I had iOS I think I would install it.
hn_throwaway_99 4y ago
It's not just that people don't know about the feature. I'd argue having the side-by-side calculator views is fundamentally different (and much better) than just having a memory-store/memory-recall button. E.g. in this app, you get to see the full equations that went into a particular set of calculations as you go back and forth.
- 4y ago

syntheticnature 4y ago

"If I had asked people what they wanted, they would have said faster horses." -- attributed, apparently wrongly, to Henry Ford. Those of us who know RPN and other options are likely to squirm at this app, but in this case the "faster horse" approach seems to be easy for people to pick up and understand.

klipt 4y ago
Horses are self driving so if you count the billions invested into self driving cars, I guess we really do want faster horses ;-)
- KaoruAoiShiho 4y ago
  Not aware of any horse from which I can watch a movie on and not have to control at all.
  - wikfwikf 4y ago
    There are plenty of accounts of drunk Victorian men letting their horses lead themselves home.
  - NoGravitas 4y ago
    Depends if the horse knows where it's going. If it's going home, no problem.

gkfasdfasdf 4y ago

Neat feature, IIRC Apple does not have a default calculator app because they can't make one that sets it apart from other apps as is the 'Apple way'. Maybe they should just adopt this one.

sbierwagen 4y ago
Both iOS and MacOS have default calculator apps. They should look familiar: he copied the interface design exactly for his app.
deleted 4y ago
[deleted]
kevinslashslash 4y ago
It's just the iPad doesn't have a default calculator app https://www.howtogeek.com/820792/where-is-the-calculator-app-on-ipad/ https://www.howtogeek.com/820792/where-is-the-calculator-app...

ape4 4y ago

I first thought it was going to show results in hex and decimal at the same time.

spc476 4y ago
I wrote my own desktop programming calculator that shows signed and unsigned decimal, octal, hexadecimal and binary at the same time. It also allows you to select 8-bit, 16-bit, 32-bit or 64-bit calculations, and do either signed extend (for converting from a lower bit to higher bit legnth) or zero extend. No floating point results though. It was a fun project to work on.

furyofantares 4y ago

This seems pretty smart to me. I think it's being dumped on because it's a "dumb" solution to something that is a non-problem for all of us here, which is probably why I've never seen this solution before. None of us would think of it. But I think it's true that while most everyone knows how to use the most basic functions of a calculator, most people don't get any further than that, and this allows them to.

codeulike 4y ago
I have a degree in Mathematics and I can never remember what C and CE buttons on a calculcator are supposed to do. If you only use them occasionally and in a hurry most calculator apps are frustratingly unfriendly.
whywhywhywhy 4y ago
Although Soulver like apps are definitely a better solution. I actually think this 2 calculator app is kinda genius in the sense that people over 60 can instantly understand it and fit it into their workflow.

mikewarot 4y ago

This UI has a better impedance match to the way he, and many people who used desk calculators, think. It's quite elegant.

PTOB 4y ago
That's a great way to use that term. I like it very much.
jiveturkey 4y ago
I find it to be very japanese. elegance expressed in such a simple form. blindingly obvious ... now. so hard to arrive at this design choice. i love this. it's poetic.

yieldcrv 4y ago

Wow, I need to look for more contrived but accepted user experiences to fix!

wishfish 4y ago

That's a brilliant & simple idea. I love it. Makes me wonder if anyone's made a small screen spreadsheet? Seems like that would be the obvious next step. Something like a default of 3x4 or 4x4 cells. Would have most of the basic spreadsheet functionality, and maybe simple graphs to show comparisons. Interface designed for touch on a six inch screen.

giarc 4y ago
I've always wanted a browser extension (or similar) that opens a small 10x10 spreadsheet so I can quickly do some calculations. For example, if you are shopping online and have various options that all have different shipping costs etc. It would be nice to do a quick breakdown of costs without having to open Excel.
- wolpoli 4y ago
  That would be a great idea! That's the perfect use for the "spreadsheet implemented in Browser" submissions we have seen over the years!
- wishfish 4y ago
  It's a little surprising Google hasn't done this already. A small (maybe inline, maybe floating) popup that gives you a little grid. Would autosave to Sheets. That would be perfect. Anyways, that's a great idea you have. I never knew I wanted this, but now I want it very badly.
  - aj7 4y ago
    If you paste an expression into the search box… Try it with (66/6)^2/2
  - themarkn 4y ago
    It’s pretty fast to pop open a new tab and visit sheets.new, I do this a lot but not everybody knows about it (and the rest of the .new TLD) The in-line floating thing is not too attractive to me. But yeah, new window, sheets.new, split screen, you’re spreadsheeting before you know it.

1970-01-01 4y ago

So he took a niche device and made it an App. Smart! https://www.casio.com/us/basic-calculators/product.DV-220/ https://www.casio.com/us/basic-calculators/product.DV-220/

pvillano 4y ago
That's a fun idea: remaking good products that no longer meet the volumes for mass production, but still have enthusiasts who could finance a limited run. Like the new Commodore 64
jiveturkey 4y ago
yo dawg, i heard you like calculators ...

anotheryou 4y ago

I can highly recommend https://bbodi.github.io/notecalc3/notecalc https://bbodi.github.io/notecalc3/notecalc Web based Soulver-like calculator that is a bit more like scripting. totally different, but wonderful.

insane_dreamer 4y ago
Nice. Gonna bookmark this one.
haint_ 4y ago
This is great, but I can't seem to copy the result. Is it just me?
- anotheryou 4y ago
  oh weird, not just you. In the export preview you can, hope there is a better way though.
- anotheryou 4y ago
  found it out: hit ctrl+c in any line (without any character selection) to copy the result.
  - haint_ 4y ago
    Thank you, but I wish we could manually select it and copy the desired part (for example when converting days to seconds I'm only concern about the actual seconds, not the "seconds" suffix)

quartz 4y ago

The best feature on the Mac's built in calculator is the paper tape (⌘+t) which I stumbled on ages ago while accidentally having the calculator open and trying to open a new tab in my browser. I always leave it open now and it has saved me countless times. Really with the iOS version had this feature built in as well.

faxmeyourcode 4y ago
Woah, thanks! This is an awesome feature I never would have found on my own
hn_throwaway_99 4y ago
Thanks for the tip! Interestingly, I found it weird how the app handles order-of-operations. That is, if you type 1 + 2 / 2, the answer shows up as 2 and the paper tape shows 1 + 2 / 2 = 2 However, if you type 1 + 2 = / 2 (that is, you type equals after the 1 + 2, which will show 3 on the screen, before typing the / 2 part), the last line of the paper type shows 1 + 2 / 2 = 1.5 They need to add some parentheses in there.
- contingencies 4y ago
  It's the accepted order of operation in maths that you resolve multiplication and division before addition and subtraction. While the single-value-view of a calculator removes visual context, if you are banging out multi-step calculations as a power user not having the standard order of operations would be odd. The workaround, as you say, is to just press enter (equals) after each required subtotal. This is pretty semantically clear, that is - if you consider a traditional keyboard to even be a thing that young people are familiar with - and that is getting arguable! Key corollary issues to the single-value-view nature of computer calculators are that they pull a lot of (now obtuse) cultural context from physical calculators plus regular mathematical context, none of which is obvious to occasional computer calculator software users. It's probably high time this stuff was rejigged. Thanks for the paper tape tip!
  - 5fOleL5Eo2So8qi 4y ago

shabbatt 4y ago

LordHeini 4y ago

Not sure if this app can do stuff like cross multiplication or run the same operations on both calculators. But this app reminded of something similar. There is an old school double mechanical pinwheel calculator: https://www.youtube.com/watch?v=qnlzKCFP0sU https://www.youtube.com/watch?v=qnlzKCFP0sU It was probably mostly used for coordinate calculations. I own one of those brunsvigas (the single stage one) and it is fascinating what these things can do. A mechanical calculator with enough didits can solve cross multiplication rather easily.

dpb1 4y ago

Some of the strong points of this calculator is the main thing I use in RPN calculators with stacks. It's so helpful for me to duplicate a value and then operate on that, and be able to throw it away if I mess up, sanity check from where I started at intermediate calculations, etc. it's not identical, but many points others are mentioning in this thread are what I value from an RPN stack based calculator. BTW, for anyone who is comfortable with RPNs, MacOS added the mode to their built-in calculator recently-ish. it's not terrible either. I've switched to it for my default experience. (even though nothing beats the HP 48g, as it's what I'm the most familiar with). Also, on the article, really cool that someone added this on mobile. I love hearing about devs developing something that fills a niche and does so well. I feel like I'm out of ideas most days. Good for her!

deepspace 4y ago
I was thinking the same thing while reading the article. I have been using RPN calculators for 40 years, and it has become second nature to manipulate the stack to have two calculations going at the same time, and then merging them, if needed.
- bollu 4y ago
  What's the RPN based calculator you use on your terminal? I'd love to learn!
  - self 4y ago
    dc, perhaps.
  - dr-neptune 4y ago
    Not sure what the parent uses, but emacs has calc, which is a RPN calculator with lots of features (including history and intermediate results) and can be used in the terminal
  - deepspace 4y ago
    To be honest, I mostly use a physical calculator (Swissmicros DM41L, which is an HP41CX clone). Second choice is the i41CX+ app on my phone. The HP41 keyboard and operational patterns were etched into my brain at university, since my first engineering calculator was an HP41C. I have used rpncalc and T_REX (https://isene.org/2021/02/T-REX.html https://isene.org/2021/02/T-REX.html) in the terminal, dc or gforth in a pinch.

asimpletune 4y ago

Improving upon the design of a calculator app is incredibly difficult. And before people complain that it's not improved, yes it is. For most people, this is way better. Congrats to him, he's living the dream. Building software that does a job, and then getting paid for that software. I just hope he doesn't suffer too many copycat apps.

FrasiertheLion 4y ago
This article made me realise why I use a python shell over a calculator app. It's nice to refer back to my previous computations and results. Several people here mention RPN; I work in tech, definitely understand stacks and get that I would be able to view my previous computations. Yet it's not something I took the time to discover, there were always other ways. I've always believed that there is still a lot of low-hanging fruit left in crafting user friendly experiences for consumer facing applications. Who would have guessed this would be the case even in the design space of something as fundamental as calculators! ~20k paid users seems surprisingly large. But I'm not plugged into the app dev scene, so perhaps this isn't unusual.
gustavorg 4y ago
> I just hope he doesn't suffer too many copycat apps. There were 2k clones of flappy bird within a month of its release. By now there must be at least a dozen programmers copying this idea (Twin-Calc) for other platforms, myself included.

jhallenworld 4y ago

My daughter is struggling with this problem: on TI-84s, "(-) 3 x^2 Enter" gives -9. Personally, I think that if you have a dedicated negation operator it should have a higher precedence than power, but at the very least the calculator could highlight what it's doing. "Hypercalc" the Android app does it, but TI-84 is the standard..

macintux 4y ago
Obligatory but futile plug for HP RPN calculators.
- cfraenkel 4y ago
  Seconded. But I'm afraid RPN is an endangered species. Who's learning it anymore?
  - kccqzy 4y ago
    Probably every computer science student learns it in order to implement something useful after learning about the stack.
Georgelemental 4y ago
> a dedicated negation operator it should have a higher precedence than power I prefer the traditional precedence; it ensures - 3 ^ 2 = 0 - 3 ^ 2
- jhallenworld 4y ago
  I understand the argument, I just wish that the most standard school calculator would highlight somehow what it's doing Another one is "2 ^ 1 / 2 Enter". Some calculators give 1, newer ones give sqrt(2).
weberer 4y ago
I'm not sure what the parenthesis around the negative sign is supposed to accomplish. Generally you put it around two or more operators.

ilos 4y ago

5fOleL5Eo2So8qi 4y ago

The hard part of writing a calculator app is not parsing `0.1` versus `.1`. That's trivial. The hard part of writing a calculator app is getting precise answers instead of floating-point answers, and given that he thinks the hard part is parsing `.1`, it probably gets it wrong.

kccqzy 4y ago
Solved by https://www.hboehm.info/new_crcalc/CRCalc.html https://www.hboehm.info/new_crcalc/CRCalc.html Also, this is in the Android stock calculator so lifting the code over is easy. See also https://dl.acm.org/doi/10.1145/2911981 https://dl.acm.org/doi/10.1145/2911981
outworlder 4y ago
That's a really large cognitive leap from such a small amount of data. Have you considered that they may not be using floating point numbers at all? They might be using arbitrary precision arithmetic. That was probably implemented by a library. So not as much effort as you would think.

xxr 4y ago

I haven't used this app, but something that makes me smile is that the paid version is only 563KB (the paid version is 4.6MB, and I suppose it's pleasant that the ad SDKs are "only" 4 megs). After seeing every major app take up 100MB+ for years, I had just assumed that there was some kind of static packaging inherent to all iOS apps that jacked the deliverable size up so high. I don't know whether Ueda was deliberately trying to get it as small as possible, or if his design is so elegant that it just naturally led to such a tiny artifact. Either way, as long as the 3.5" floppy is still in its sunset period[0], I suppose it's nice that there's modern software that will still fit on it. [0]https://www.bbc.com/news/world-asia-62749310 https://www.bbc.com/news/world-asia-62749310

auggierose 4y ago
If it is an app built in Swift, then iOS and macOS ship already with all of its runtime libraries, so the app itself can be very small.
Someone 4y ago
> there was some kind of static packaging inherent to all iOS apps There was for apps using Swift. Before the Swift ABI was frozen, iOS apps using Swift had to statically link the Swift standard library. Nowadays, iOS provides it as a dynamic library. (and having a stable ABI is quite an accomplishment for a language like Swift. See https://faultlore.com/blah/swift-abi/ https://faultlore.com/blah/swift-abi/)
- saagarjha 4y ago
  The Swift libraries are not all that large, perhaps a dozen MB or so.
postalrat 4y ago
The web app version would probably be 1/10th of that.
- miniBill 4y ago
  I mean... it depends what you want to support. My web calculator [fully client side] is 370kb of JS. It has features that this doesn't have (3d rendering, solving equations), but doesn't have code that this needs (mostly, the keyboard)...

ctrlc-root 4y ago

If you're looking for something similar on the desktop I use SpeedCrunch to address the same need. You can chain calculations and refer back to previous entries while seeing your history. https://heldercorreia.bitbucket.io/speedcrunch/ https://heldercorreia.bitbucket.io/speedcrunch/

mjcohen 4y ago
Can't open it on MacOS Monterey because owner cannot be verified.

jjnoakes 4y ago

It'd be cool to take this a step further - allow for a tree-like setup of as many calculators as you want. Each number in one calculator's equation could be expanded out into a separate calculator where the number was computed, etc.

pyinstallwoes 4y ago
Memoize and precompute every calculation over a merkle tree distributed on a decentralized network using content addressable memory hashed to every calculation as the hash you say? Yeah love it.
- jjnoakes 4y ago
  Did you reply to the right comment? I'm not sure I follow...

supernova87a 4y ago

> ...Ueda recalled, "I thought it'd be easy, but it was unexpectedly hard." ... For example, while there are users who input 0.5 by tapping "0," the decimal point, and then "5," there are also users who only input the decimal point and "5," while omitting the "0." He said, "There were around 100 types of these sort of conditions, and it was a lot of work to solve them." I wonder what other kinds of non-trivial calculator behaviors he had to rediscover from scratch?

thrdbndndn 4y ago
About this specific case: I also never knew using ".5" to mean "0.5" is a thing, until I lived in the US. Not sure if it's a US thing or Western world thing, my country (not Japan, but also in East Asia) just doesn't use it.
- Ferrotin 4y ago
  Probably your calculators all support it.
  - thrdbndndn 4y ago
    Yeah they do, just didn't know this notation (convention?).
    - Ferrotin 4y ago
      Oddly, I don’t think I’ve ever noticed the zero being omitted except casually or to save space in a table, in English. I would expect ordinary writing to include the zero.
- NavinF 4y ago
  That's surprising. People don't say stuff like "try setting power level to point three"? Do they use a different word for the decimal separator?
  - 4y ago

indigodaddy 4y ago

Simple and effective.

vertis 4y ago

I quite like Numi[0] (Mac), also available as part of SetApp[1] [0]:https://numi.app/ https://numi.app/ [1]: https://setapp.com/apps/numi https://setapp.com/apps/numi

layer8 4y ago

This would almost be unnecessary if iOS allowed two instances of the same app to be opened (and displayed in split view). I’m saying “almost” because the integrated app is of course easier for non power users.

injidup 4y ago

A spreadsheet with two cells only. Take that bloatware excel!

jiveturkey 4y ago
underrated comment

aj7 4y ago

A huge strength of the original HP9100A programmable calculator, http://archive.computerhistory.org/resources/text/HP/HP.9100A.1968.102646164.pdf http://archive.computerhistory.org/resources/text/HP/HP.9100..., was that ALL 3 rpn stack registers were visible AT ONCE ON THE CRT. So he has resurrected the original blank slate engineer’s intent; Osborne realized that people would be uncomfortable “knowing” stuff was in hidden registers, as apparently a great deal of non-technical people are today, 52 years later.

Severian 4y ago
Wow, that's a good looking brochure. I always loved that style of illustration.

WalterBright 4y ago

I'm actually kind of shocked. The calculator apps emulate a calculator, but they don't take any advantage of having the phone screen. A proper calculator app would allow you to type 1.6*2/3 and display the equation on the screen, not just the 3.

newtritious 4y ago
This one does: https://jacobdoescode.com/technicalc https://jacobdoescode.com/technicalc
- WalterBright 4y ago
  That looks pretty sweet!
  - WalterBright 4y ago
    dang, IOS 13 or later.

icedistilled 4y ago

Why don't calculator apps at the very least display the current calculation like the casio FX-95? The current options of basic or scientific for mac/ios would be 100x better. The ticker tape only partially solves it. FX 95: https://www.casio.com/intl/scientific-calculators/product.FX-95MS/ https://www.casio.com/intl/scientific-calculators/product.FX...

qwezxcrty 4y ago

I don't see how this works better than any scientific calculator that shows history. Also don't understand why he put two sets of keyboards, to me it just doesn't make sense. Marginally related: if you are looking for a non-sucking calculator app on desktop or mobile, try an emulator of a (modern or retro, at your choice) HP or TI graphical calculator. My personal favorite is the emulator of HP Prime.

codeulike 4y ago
Its immediately intuitive without having to think about it. Its two calculators. Its magnificent.
NavinF 4y ago
Umm of course history is superior. So are named variables. You and me are not the target audience. Ever noticed how normal people hit both C and CE several times on physical calculators because it's not obvious what those buttons do? That's the target audience.

imhoguy 4y ago

Is it only me who sees a humble man enjoying his own ikigai[0] in simple but challenging creation? The photo says it all. [0]https://en.wikipedia.org/wiki/Ikigai https://en.wikipedia.org/wiki/Ikigai

chongli 4y ago

It’s interesting but the duplicate sets of buttons are a big waste of space. My favourite free calculator app is Desmos Scientific (by the makers of the graphing calculator) [1]. This app gives you as many entry lines as you like and they all remain live. You can also define variables and functions in one line and use them in another. In effect, it’s like a single column from a spreadsheet. [1] https://apps.apple.com/ca/app/desmos-scientific-calculator/id1235292051 https://apps.apple.com/ca/app/desmos-scientific-calculator/i...

aasasd 4y ago

Total Commander and Ghost Commander on Android solve the problem of two panels in the portrait orientation by displaying one of them and having a button to switch to the other one. However, seeing as some of the success of this calculator app is probably attributed to the ‘memory’ function being non-obvious to people, I'd guess that a hidden calculator might also put some off.

gfodor 4y ago

If you liked this app, stay tuned - I am working on a 3-calculator app that increases the utility of this app by up to 50%.

misterprime 4y ago
LOL, can you make it dynamically have as many calculators as there are cores on the CPU and guarantee that each calculator only uses a single unique core for its own calculations?
- BowBun 4y ago
  I don't think you need to limit the number of calculators to the number of cores. You can just store the history/results somewhere on disk or in memory. Which core doing the work when you press '=' doesn't really matter in this case unless you're load-testing this calculator.
- megablast 4y ago
  I mean, why?? Do you think the calculator is a heavy CPU view??? You still only use one at a time anyway. And yes, you could easily have 10,000 calculators or more.
  - misterprime 4y ago
    Thanks, sorry. It was just a silly response to a silly comment.
insane_dreamer 4y ago
but does it run on the GPU?
- TheOtherHobbes 4y ago
  The calculations are the output of an ML solver trained on a data set generated by corporate accountants.

TheSpiceIsLife 4y ago

Any software calculator that has a tape feature works well for me, I think the built in windows calc app does. I've been using CalcTape for a few years now, it's a calculator and notepad in one. https://www.schoettler-software.com/en/calctape/windows https://www.schoettler-software.com/en/calctape/windows I appreciate the simplicity of the side by side calculator app though.

savrajsingh 4y ago

This is the perfect example of how we, as devs, way overthink what people actually want / are comfortable with.

fyloraspit 4y ago

This is basically the same reason I default to speedcrunch for my calculator app. It has a nice visible and interactive history of calculations.

iisan7 4y ago
Currently a big fan of https://clcalc.net/ https://clcalc.net/. I went through calculator withdrawal after I left Windows XP and the great (for its time) Powertoy Calculator at https://www.rarst.net/software/powertoy-calculator/ https://www.rarst.net/software/powertoy-calculator/. I wanted to like speedcrunch but I abandoned it, because I've found that it takes longer to load (4-5 seconds or more) than I need to have it open (1-2 seconds).
- haint_ 4y ago
  Thanks, it works great, but I found it better to have 2 sides: expressions on the left and results on the right. Maybe I'm already too familiar with Numi, lol.

FilterSweep 4y ago

> It is also possible to perform different computations on each calculator. This function comes in handy when the user wants to compare prices to determine which store product is cheaper by the gram, for example. This adds another use-case outside of the M functions on a standard calc :)

cobaltoxide 4y ago

Personally I find it embarrassing that we use a device with gigabytes of RAM and millions of pixels to emulate a 19-button device from half a century ago.

pvillano 4y ago
It's probably hard to come up with a better interface. A pocket calculator can be operated with very little cognitive load. It's easy to memorize because things don't move and it's easy to discover because ~every action is always visible. It's also good enough. Most people don't need more than a pocket calculator. Sometimes I use WolframAlpha, very modern, but I type my query on a keyboard whose design predates the calculator (QUERTY in <1873 vs "10-key" calculator in 1902)
- cobaltoxide 4y ago
  I like to use a REPL (like MATLAB or Python) where I can enter expressions with a real keyboard instead of hunting and pecking the skeumorphic calculator GUI. This also allows me to see the history of my calculations without resorting to the weird mirrored calculator. Even something like a TI-85 graphing calculator offers this.
fomine3 4y ago
Yeah buttons should be rendered with ray tracing and deep learning

Mathmanjetson 4y ago

asimjalis 4y ago

This can also be used for what if scenarios based on an intermediate result.

angry_octet 4y ago

New calculator feature request: export the calculation stream to the clipboard and CSV/excel, same as old paper tape calculators.

DangitBobby 4y ago

I love this! Also, today I learned that you can scroll through your history in the built-in android calculator by swiping down on the number input field!

Ferret7446 4y ago

How odd. I see a lot of discussion about calculators having history and such, but as someone who became acquainted with Emacs's Calc mode at an early age, it seems so strange that calculators with history are a foreign concept to most people.

MandieD 4y ago
The vast majority of people outside of Unix-adjacent computing have never heard of, much less used, emacs. More broadly, most people have never used any form of REPL, including the handy PowerShell that has come out of the box with Windows for a good decade now. This app succeeds because the developer has hit upon an interface that better matches normal users' mental models around calculators.

waynesonfire 4y ago

it's also less keystrokes relative to M/MR/MC technique when chaining computation, since, you have two calculators enable concurrency.

ChicagoBoy11 4y ago

What a fantastic example of "make something people want." Kudos to him... and so inspiring!

WiSaGaN 4y ago

This is the innovation that everybody would see how obvious it is once it's out. And yet no one thought about making it for a very long time.

noobermin 4y ago

I think this is why I prefer using the python idle as a calculator. You can assign an expression to a variable, but you can always scan up (assuming your terminal window is tall enough) to see what expression you used to calculate it. People are saying how this is the point of memory on calculators but once you save to M you basically need to remember what's in there. Seeing what you did to calculate whatever is better. In a way then, the python idle is like this but with many calculators side by side.

bee_rider 4y ago
Python is fine, although I find that Octave gets me to "doing a calculation" in a couple fewer keypresses.
Georgelemental 4y ago
I like qalc (https://github.com/Qalculate/libqalculate https://github.com/Qalculate/libqalculate) as a command-line calculator. It has all the basic repl features, but also excellent units support and other useful math-oriented things.

deleted 4y ago

[deleted]

mrb 4y ago

What I want is a phone app calculator that works like the Python REPL/console. Save ALL previous calculations. Display the last dozen or so. Can scroll through them. Tap on one to recall it, edit one number, recompute. Done. This would beat by far the convenience and usability of this 2-in-1 calculator. I would KILL to have this. In fact, on my laptop, I use the Python REPL as a calculator. I hit Ctrl-T python ENTER. It opens a terminal and I start typing 48*152 ENTER and I see the result. The history of calculations is saved. I can access previous calculations, edit one number and recompute. I see the last 100 lines or so, on one screen. The only one somewhat usable Python REPL on Android is "Pyonic Python 3 interpreter" but it's clumsy to use as a calculator because it uses the standard alphabetic keyboard so you have to keep switching to the special characters layout to type math operators (-+/...) If this ONE detail would be fixed, and with some minor UI polish I believe it could become more popular than the 2-in-1 calculator...

adriansky 4y ago
Exactly! I created calculator app with history for this reason. It also allows you to copy and paste from past results. - iOS: https://apps.apple.com/us/app/instant-calculator/id1632328821 https://apps.apple.com/us/app/instant-calculator/id163232882... - Android: https://play.google.com/store/apps/details?id=com.adrianmejia.calculator https://play.google.com/store/apps/details?id=com.adrianmeji...
Georgelemental 4y ago
qalc (https://github.com/Qalculate/libqalculate https://github.com/Qalculate/libqalculate) is my command-line calculator of choice. Its killer feature IMO is the units support
- mrb 4y ago
  Very cool ! For units conversion I use GNU Units. But qalc seems to combine the benefits of both the Python REPL and GNU Units. I just tried the command-line version and noticed it doesn't support recalling the history (UP arrow) and editing calculations. This is unfortunately a deal-breaker :-( Don't have time to submit a patch.

pyinstallwoes 4y ago

Reminds me of a two stack push down automata. Stack programming languages. Forth lang.

jiveturkey 4y ago

it's too bad i can only buy one copy of this app. if only apple would allow the purchase of 2 copies. but the universe might collapse then, having reached its poetic end.

easygenes 4y ago

For me the killer convenience calculator on mobile has been Soulver. The UI is just perfect for making it easy to string together calculations without taking up too much screen real estate. Irritatingly, the Mac app is available still, but it has been pulled from the iOS App Store for a long time, and it’s not on any other platforms. If something like Soulver existed cross platform I would have it installed on everything.

hnjst 4y ago

I'm still completely baffled that we nowadays almost all have in our pocket a device able to run something like https://f-droid.org/en/packages/jp.yhonda/ https://f-droid.org/en/packages/jp.yhonda/.

ycombinete 4y ago

Just bought this for my iPad, which apple inexplicably doesn’t bundle with their calculator app.

chacha21 4y ago

An opportunity to post again my thoughts about software calculators ! https://chachatelier.fr/chalk/article/chalk.html https://chachatelier.fr/chalk/article/chalk.html

Liquid_Fire 4y ago
Have you ever tried Qalculate? I don't see it mentioned in your article. It feels like it addresses most of your points for creating Chalk, and it's already cross-platform.
- chacha21 4y ago
  Most people didn't understand that my goal was not to benchmark all existing calculator apps. It is on purpose that I did not mention all "pretty good" softwares, because I cannot know them all. The article I wrote wants to mention every point that should be adressed (in my opinion) to make a good calculator. Qalculate, like many others, does address some of them. But as far as I know, only Chalk addresses all of them.

tempodox 4y ago

This is such a nice example of how relatively simple ideas can still be of huge utility.

mfbx9da4 4y ago

This epitomizes my passion for coding -- it's the lowest barrier to entry for being an inventor

frou_dh 4y ago

Similar to the 80-something Japanese woman who created an iPhone app relating to a doll festival, that was a big news story a couple of years ago.

adrianomartins 4y ago

Wow, this is some inspiration right here. Never too late! Also, do you have a pain, build a solutions! Congrats to that retired engineer!

pluijzer 4y ago
> Never too late! From your comment and some other comments and the way the article is written I gather that the engineers age is seen as something novel. Do people really see 63 as an newsworthy fact? Not trying to troll, I honestly wonder. It is 4 years from retirement in my country and I see many other achievements come from much older people. I just don't see 63 as anything special or old.
- Sebb767 4y ago
  It's unusual for people in that age group to be good with computers, as they grew up without them (or at least without them being as ubiquitous as in the last few decades). It's also pretty rare to hit such a sweet spot with an app, which makes it somewhat unusual that someone from that age group managed to do so.

mavhc 4y ago

Wait until they try a GUI with windows

runeks 4y ago

> For example, while there are users who input 0.5 by tapping "0," the decimal point, and then "5," there are also users who only input the decimal point and "5," while omitting the "0." The practice of including punctuation inside the quote makes this a somewhat confusing sentence, at least if you’re used to using a comma instead of a period for the decimal point.

effnorwood 4y ago

fennecfoxy 4y ago

Really cool project for a retired engineer to do. Kind of reminds me of the "Notebooks" concept that Jupyter and others use (I dipped my toes in it, not an expert). Would be nice if he could abstract the calculators to a list/hierarchy of calculations performed, then be able to "open" limitless additional calculators as desired and swipe between 'em. Being able to see a hierarchy of calculations and say, go back to a parent one and modify the value or part of the calculation itself and have child ones update would be super cool.

supermatt 4y ago

Fantastic! A great example of a simple product that people want/need.