Stories
Slash Boxes
Comments

SoylentNews is people

posted by mrpg on Friday March 16 2018, @12:35AM   Printer-friendly
from the ∫-√(1+[f(x)']²)dx dept.

Suppose, a litre of cola costs US$3.15. If you buy one third of a litre of cola, how much would you pay?

The above may seem like a rather basic question. Something that you would perhaps expect the vast majority of adults to be able to answer? Particularly if they are allowed to use a calculator.

Unfortunately, the reality is that a large number of adults across the world struggle with even such basic financial tasks (the correct answer is US$1.05, by the way).

[...] In many other countries, the situation is even worse. Four in every ten adults in places like England, Canada, Spain and the US can't make this straightforward calculation – even when they had a calculator to hand. Similarly, less than half of adults in places like Chile, Turkey and South Korea can get the right answer.

-- submitted from IRC

High number of adults unable to do basic mathematical tasks


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 2) by HiThere on Friday March 16 2018, @05:25AM (3 children)

    by HiThere (866) Subscriber Badge on Friday March 16 2018, @05:25AM (#653390) Journal

    The problem is if a liter costs $3.15, it's probably true that a third of a liter costs $3.15. Most places aren't willing to split things like that.

    --
    Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
    Starting Score:    1  point
    Karma-Bonus Modifier   +1  

    Total Score:   2  
  • (Score: 2) by theluggage on Friday March 16 2018, @10:01AM (2 children)

    by theluggage (1797) on Friday March 16 2018, @10:01AM (#653481)

    Well, the litre certainly won’t cost $3.15, it will be $2.97 or something, and if the 1/3 litre option exists it will cost something like $1.29... A cynic might think that retailers were deliberately obfuscating things. At least, in countries that use litres, the sales tax is more likely to be rolled into the sticker price...

    Learning how and when to divide and multiply - and especially to make estimates (I.e. knowing that the cost should be about $1) is important, but quick fire mental arithmetic that only works with conveniently chosen numbers is just a party trick with limited real-world value that, sadly, has become a sort of totem for intelligence. It’s great for those that are good at it, but for others it’s really training them to panic and blank when faced with a math problem.

    If people couldn’t answer that question with a calculator then that’s worrying- but over emphasis on mental maths could be part of the problem, not the solution.

    • (Score: 2) by AthanasiusKircher on Friday March 16 2018, @01:14PM (1 child)

      by AthanasiusKircher (5291) on Friday March 16 2018, @01:14PM (#653569) Journal

      Well, the litre certainly won’t cost $3.15, it will be $2.97 or something

      Depends. One scenario where prices like $3.15 are common in some shops is where taxes might make the final price add up to an even number. Shops that do a lot of cash business frequently encourage that in their pricing.

      At least, in countries that use litres, the sales tax is more likely to be rolled into the sticker price...

      As far as I know, all (or almost all) countries use litres to measure things like soda. One-litre and two-litre bottles are standard in the U.S. for larger sizes and have been for decades. 1/3 of a litre, not so much -- but I don't think that exact size is common anywhere in the world.

      Learning how and when to divide and multiply - and especially to make estimates (I.e. knowing that the cost should be about $1) is important, but quick fire mental arithmetic that only works with conveniently chosen numbers is just a party trick with limited real-world value that, sadly, has become a sort of totem for intelligence.

      In general, I agree with some of this. Mental math is not a hugely important skill these days when every electronic device around you probably has a built-in calculator. I'd disagree a bit that "mental arithmetic... only works with conveniently chosen numbers." There are lots of tricks used to handle all sorts of numbers, and back in the day, any scientist or engineer actually good at it could often handle a lot more arbitrary numbers and even advanced operations through knowledge of values of a few functions at certain values.

      All that said, in this particular case, if you can't do the division in your head, I think you're missing some fundamental concepts of numerical literacy/numeracy (or "number sense"). Everyone should be able to divide 3/3 = 1 and 15/3 = 5. And if you think you need to use calculators for basic arithmetic facts... well, I question what these people got out of math classes in school. All states in the U.S. require geometry and algebra I at least for graduation, and many require or encourage algebra II. I've actually taught in high schools, and I can tell you how weird it is trying to teach students who can't figure out that 15/3 = 5 without a calculator. How exactly do they follow anything you do in an algebra class?? If you put 3x = 15 on the board, and then you write x =5 next, you need them to follow quickly. It was very clear that my students who hadn't mastered fundamental arithmetic facts had a lot of trouble in algebra, just because they couldn't follow even the most basic algebraic operations. (And I challenge people to come up with a way to teach even basic algebra with some example problems without relying on some knowledge of basic arithmetic.)

      So, then we get to the problem in question here: $3.15 divided by 3. It's even nicely divided into dollars and cents for you. Even an elementary school kid should conceptualize that as 3 of one thing (dollars) and 15 of another (cents), and both of those are easily divisible by 3. This is not advanced mental arithmetic or parlor tricks -- it's basic number sense. Excusing this as an example of "mental math" that's unnecessary is like saying, "Okay, I know you're supposed to be literate and know how to read, but all those pesky words with hyphens in the middle... I know you can't read them. That's advanced mental reading manipulation -- only a parlor trick useful in texts with a lot of hyphenations."

      If people couldn’t answer that question with a calculator then that’s worrying

      Agreed.

      • (Score: 2) by theluggage on Wednesday March 21 2018, @10:46AM

        by theluggage (1797) on Wednesday March 21 2018, @10:46AM (#656029)

        Everyone should be able to divide 3/3 = 1 and 15/3 = 5.

        Sure - but that's useless unless you understand enough about place notation to know that is a valid way of doing it.., and if the value was $3.17, you're stuffed. Oh, and I'll guarantee that you'll get a lot of "$3.5s" or "$3.50s" amongst the answers. That's just one of many, many tactics for mental arithmetic.

        One common feature of modern curricula is "number talk" sessions designed to explore strategies for solving such problems - then one little girl goes home, Mum asks her what they did in math today, and she says they spent the lesson talking about how to divide 3.15 by 3 and you've got a backlash against "namby-pamby modern teaching" on your hands.

        I've seen a few mental arithmetic tests in my time and know the routine: if you're asked to "calculate" then the number will be 3.15 (or similar). if you're asked to "estimate" then it will be $2.99. $3.17/3 doesn't happen in such tests because it will get thrown out as too hard.

        If I was writing a real-word numeracy question I would - for example - present kids with a pile of labels advertising various 3-for-2 and BOGOF offers and get them to sort them into 3 piles: rip-off, good deal, no difference... and be sure to include awkward numbers. Extra marks for pointing out that the 3-for-2 offer on bags of bananas is only good value if you are likely to eat that many before they rot (a lot of math nerds would fail that one).

        Anyway, all sides of the education debate are guilty of false dichotomies - teach tables vs. teach coping strategies, teach real-wold-skills vs. teach algebra, understanding vs. facts.... they're not either/or choices, but its a case of getting the right balance. The big problem at the moment is the obsession with measurement that means that what kids are mostly learning is how to do test questions that have been contrived to be cheap and easy to administer.