6 ms·

Why do you think that every functioning adult should understand algebra?

trendia 9y ago
Is it cheaper to buy 1 case of water for $2.50 or 3 cases of water for $9.00 ? If you get a $1,000 loan at 1% interest each month, how much will you owe in 1 year? You can buy a phone for $500 or pay Verizon $16.70 / month for 36 months. Which is cheaper?
- deleted 9y ago
  [deleted]
- bcruddy 9y ago
  > If you get a $1,000 loan at 1% interest each month, how much will you owe in 1 year? Pe = nRT is actually the first thing taught in calc 1.
- vmarsy 9y ago
  > Is it cheaper to buy 1 case of water for $2.50 or 3 cases of water for $9.00 Slightly off topic as I don't think this is college level algebra, in supermarkets in Europe they are required by law to put the "€/liter" price in small on the side, so you can compare easily. In the US it doesn't seem mandatory, or at least the unit is not mandatory because sometimes they use fl oz, sometimes gallons, or for pieces of meat sometimes oz, sometimes lbs, so when you want to compare the prices of 2 similar items, what would just take you 0.5 sec in Europe takes you much longer in the US since you need to add unit conversion in the mix. For example here your "cases" could be of different sizes, that 1 case of water could be 2L ,while those 3 cases could be a gallon each...
  - dozzie 9y ago
    > [...] in supermarkets in Europe they are required by law to put the "€/liter" price in small on the side, so you can compare easily. Yeah, and then you get aggregate price in "€/package", except that packages are of different size.
    - majewsky 9y ago
      Or they switch between "€/kg", "€/100 g", "€/liter", and "€/package" seemingly randomly.
- bsder 9y ago
  I don't need algebra for 2 of those. I need the ability to do fast mental arithmetic. And a shop math class would be far more useful for that. As for compound interest, you need WAY more than algebra ...
  - throwawayjava 9y ago
    > I don't need algebra for 2 of those. All of these are literally the sorts of things you'd find on homework assignments and final exams in a community college algebra course... You do need algebra, and don't realize how difficult this "trivial" algebra is for some students because you can do it without even realizing you're doing it. I mean, there will be some FOIL and quadratic equation examples as well. And a bunch of stuff in-between like identifying graphs of functions. But CC Algebra is super bimodal, so it's probably not the case that students are nailing these word problems and only failing with the other stuff.
nanolith 9y ago
I think that trendia already touched on a lot of these, but consider the typical every day problems that require algebra to solve: An item at the store is listed for $4.99 each, but under a promotion, the item is buy two, get one free. What is the net cost of each item? If I am driving at 20 miles per hour, it takes my vehicle 20 feet to stop. If I am driving at 40 miles per hour, how much distance will it take my vehicle to stop? I have a 20 foot ladder. It is leaning against a wall such that the tip of the ladder is touching the top of the wall. The distance between the bottom of the ladder to the bottom of the wall measures 10 feet. What is the height of the wall? You and three office mates decide to purchase fast food for lunch. Each of you order the same item, and your three office mates give you $10 each. The cashier rings up $35.17 as the total. How much change do you owe each of your office mates? You are traveling by bus and wish to estimate your time of arrival. You notice that it takes one minute and 25 seconds for the bus to travel from one mile marker to the next. Your destination is fifty miles away. Assuming the bus stays at the same speed, how long until you reach your destination? If these seem contrived, then consider that just about every college educated adult, at one time or another, will need to know his or her way around a spreadsheet. Even basic spreadsheet formulas make little sense unless one can reason algebraically. Just trying to learn how to use a spreadsheet program without understanding algebra is a painful process.
- bryanlarsen 9y ago
  What a great illustration of the one of the problems with math education: Q: If I am driving at 20 miles per hour, it takes my vehicle 20 feet to stop. If I am driving at 40 miles per hour, how much distance will it take my vehicle to stop? A: This can only be answered experimentally for a given car, tire condition & road condition, but a rough estimate would be to apply the square law naively, giving an answer of 80 feet, but of course that's very approximate. The only correct answer that can be given is "more than 40 feet".
  - nanolith 9y ago
    Yes. It can only be answered experimentally, but the Square Law still applies, with constants to account for reaction time and friction. The point is that someone who has studied Algebra would be able to recognize a polynomial in the data and could match the data to a reasonable function just by taking measurements. That is the power of Algebra, and it is something that all adults should possess.

Is it cheaper to buy 1 case of water for $2.50 or 3 cases of water for $9.00 ? If you get a $1,000 loan at 1% interest each month, how much will you owe in 1 year? You can buy a phone for $500 or pay Verizon $16.70 / month for 36 months. Which is cheaper?

deleted 9y ago
[deleted]
bcruddy 9y ago
> If you get a $1,000 loan at 1% interest each month, how much will you owe in 1 year? Pe = nRT is actually the first thing taught in calc 1.
vmarsy 9y ago
> Is it cheaper to buy 1 case of water for $2.50 or 3 cases of water for $9.00 Slightly off topic as I don't think this is college level algebra, in supermarkets in Europe they are required by law to put the "€/liter" price in small on the side, so you can compare easily. In the US it doesn't seem mandatory, or at least the unit is not mandatory because sometimes they use fl oz, sometimes gallons, or for pieces of meat sometimes oz, sometimes lbs, so when you want to compare the prices of 2 similar items, what would just take you 0.5 sec in Europe takes you much longer in the US since you need to add unit conversion in the mix. For example here your "cases" could be of different sizes, that 1 case of water could be 2L ,while those 3 cases could be a gallon each...
- dozzie 9y ago
  > [...] in supermarkets in Europe they are required by law to put the "€/liter" price in small on the side, so you can compare easily. Yeah, and then you get aggregate price in "€/package", except that packages are of different size.
  - majewsky 9y ago
    Or they switch between "€/kg", "€/100 g", "€/liter", and "€/package" seemingly randomly.
bsder 9y ago
I don't need algebra for 2 of those. I need the ability to do fast mental arithmetic. And a shop math class would be far more useful for that. As for compound interest, you need WAY more than algebra ...
- throwawayjava 9y ago
  > I don't need algebra for 2 of those. All of these are literally the sorts of things you'd find on homework assignments and final exams in a community college algebra course... You do need algebra, and don't realize how difficult this "trivial" algebra is for some students because you can do it without even realizing you're doing it. I mean, there will be some FOIL and quadratic equation examples as well. And a bunch of stuff in-between like identifying graphs of functions. But CC Algebra is super bimodal, so it's probably not the case that students are nailing these word problems and only failing with the other stuff.

nanolith 9y ago

I think that trendia already touched on a lot of these, but consider the typical every day problems that require algebra to solve: An item at the store is listed for $4.99 each, but under a promotion, the item is buy two, get one free. What is the net cost of each item? If I am driving at 20 miles per hour, it takes my vehicle 20 feet to stop. If I am driving at 40 miles per hour, how much distance will it take my vehicle to stop? I have a 20 foot ladder. It is leaning against a wall such that the tip of the ladder is touching the top of the wall. The distance between the bottom of the ladder to the bottom of the wall measures 10 feet. What is the height of the wall? You and three office mates decide to purchase fast food for lunch. Each of you order the same item, and your three office mates give you $10 each. The cashier rings up $35.17 as the total. How much change do you owe each of your office mates? You are traveling by bus and wish to estimate your time of arrival. You notice that it takes one minute and 25 seconds for the bus to travel from one mile marker to the next. Your destination is fifty miles away. Assuming the bus stays at the same speed, how long until you reach your destination? If these seem contrived, then consider that just about every college educated adult, at one time or another, will need to know his or her way around a spreadsheet. Even basic spreadsheet formulas make little sense unless one can reason algebraically. Just trying to learn how to use a spreadsheet program without understanding algebra is a painful process.

bryanlarsen 9y ago
What a great illustration of the one of the problems with math education: Q: If I am driving at 20 miles per hour, it takes my vehicle 20 feet to stop. If I am driving at 40 miles per hour, how much distance will it take my vehicle to stop? A: This can only be answered experimentally for a given car, tire condition & road condition, but a rough estimate would be to apply the square law naively, giving an answer of 80 feet, but of course that's very approximate. The only correct answer that can be given is "more than 40 feet".
- nanolith 9y ago
  Yes. It can only be answered experimentally, but the Square Law still applies, with constants to account for reaction time and friction. The point is that someone who has studied Algebra would be able to recognize a polynomial in the data and could match the data to a reasonable function just by taking measurements. That is the power of Algebra, and it is something that all adults should possess.