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Try this on a non-RPN calculator 3 + 4 7 + 8 ----- + ----- 5 + 6 9 + 2

by jonsen 12y ago

Macha 12y ago
<fraction button> 3 + 4 <down> 5 + 6 <right> + <fraction button> 7 + 8 <down> 9 + 2 = (19 button presses) Or: ((3 + 4) / (5 + 6)) + ((7 + 8) / (9 + 2)) (27 button presses) vs on RPN: + / + 3 4 + 5 6 / + 7 8 + 9 2 (I think? I don't use RPN) (15 button presses) I guess 19 vs 15 button presses is a tradeoff I'm willing to make for easier understanding.
- jonsen 12y ago
  RPN: 3 (enter) 4 + 5 (enter) 6 + / 7 (enter) 8 + 9 (enter) 2 + / +
  - DougBTX 12y ago
    So 19 presses too, that's got a nice "essential complexity" feel to it.
- jonsen 12y ago
  Fine, if you can "paint" the full equation on your calculator. But on simpler calculators people may have a hard time getting it right. 3 + 4 = / ( 5 + 6 = + ( 7 + 8 ) / ( 9 + 2 =
- sukilot 12y ago
  You can elide one pair of parens. You forgot the R part of RPN.
- lambda 12y ago
  I'm not familiar with the fraction button. Is this common on calculators? I don't see it on most of the basic function calculators that I look at. Hmm, taking a look around, it looks like it might be present on a lot of scientific calculators, but not the basic calculators I see. I had switched to RPN by the time I started using scientific calculators, so I guess I never became familiar with this button. Parentheses are common on scientific caclulators and graphing calculators, but as you demonstrate, they add a lot of extra button presses, and you even left out the final "=". To do this on an RPN calculator, you need nothing beyond the basic 4 functions and the enter key, while you need extra specialized keys like parens or a fraction button to do it on an infix calculator. Taking a look at various infix scientific calculators, they mostly seem to have both parens and a fraction key, so using up the space of 3 keys that an RPN calculator doesn't need and can use for more actual functionality. Here's how you do it on RPN: 3 <enter> 4 + 5 <enter> 6 + / 7 <enter> 8 + 9 <enter> 2 + / + You wrote it in Polish notation rather than Reverse Polish Notation, and had left out the enter key that is used as the delimiter between two numbers (pushes a number to the stack, so you can start entering the next number).

Try this on a non-RPN calculator 3 + 4 7 + 8 ----- + ----- 5 + 6 9 + 2

by jonsen 12y ago

Try this on a non-RPN calculator 3 + 4 7 + 8 ----- + ----- 5 + 6 9 + 2

Macha 12y ago

<fraction button> 3 + 4 <down> 5 + 6 <right> + <fraction button> 7 + 8 <down> 9 + 2 = (19 button presses) Or: ((3 + 4) / (5 + 6)) + ((7 + 8) / (9 + 2)) (27 button presses) vs on RPN: + / + 3 4 + 5 6 / + 7 8 + 9 2 (I think? I don't use RPN) (15 button presses) I guess 19 vs 15 button presses is a tradeoff I'm willing to make for easier understanding.

jonsen 12y ago
RPN: 3 (enter) 4 + 5 (enter) 6 + / 7 (enter) 8 + 9 (enter) 2 + / +
- DougBTX 12y ago
  So 19 presses too, that's got a nice "essential complexity" feel to it.
jonsen 12y ago
Fine, if you can "paint" the full equation on your calculator. But on simpler calculators people may have a hard time getting it right. 3 + 4 = / ( 5 + 6 = + ( 7 + 8 ) / ( 9 + 2 =
sukilot 12y ago
You can elide one pair of parens. You forgot the R part of RPN.
lambda 12y ago
I'm not familiar with the fraction button. Is this common on calculators? I don't see it on most of the basic function calculators that I look at. Hmm, taking a look around, it looks like it might be present on a lot of scientific calculators, but not the basic calculators I see. I had switched to RPN by the time I started using scientific calculators, so I guess I never became familiar with this button. Parentheses are common on scientific caclulators and graphing calculators, but as you demonstrate, they add a lot of extra button presses, and you even left out the final "=". To do this on an RPN calculator, you need nothing beyond the basic 4 functions and the enter key, while you need extra specialized keys like parens or a fraction button to do it on an infix calculator. Taking a look at various infix scientific calculators, they mostly seem to have both parens and a fraction key, so using up the space of 3 keys that an RPN calculator doesn't need and can use for more actual functionality. Here's how you do it on RPN: 3 <enter> 4 + 5 <enter> 6 + / 7 <enter> 8 + 9 <enter> 2 + / + You wrote it in Polish notation rather than Reverse Polish Notation, and had left out the enter key that is used as the delimiter between two numbers (pushes a number to the stack, so you can start entering the next number).