|Photo: Kevin Knudson|
It's been quite a year for mathematics problems on the Internet - three questions have been online everywhere, causing consternation and head-scratching and blowing the minds of adults worldwide as examples of what kids are expected to know these days.
|Photo: Flickr / Robert Couse-Baker|
As a mathematician, I suppose I should subscribe to the 'no such thing as bad publicity' theory, except that problems of this ilk a) usually aren't that difficult once you get the trick, b) sometimes aren't even math problems and c) fuel the defeatist 'I'm not good at math' fire that pervades American culture.
The inability to solve such a problem quickly is certainly not indicative of a person's overall math skill, nor should it prompt a crisis of confidence about the state of American math aptitude.
When is Cheryl's birthday?
In April, the Internet erupted with shock that 10-year-olds in Singapore were asked to answer the following question on an exam.
Except that it wasn't for elementary school students at all; rather it appeared on an Asian Olympiad exam designed for mathematically talented high school students. What's more, this isn't even a math problem, but a logic problem. It's true that students tend to learn formal logic via mathematics (plane geometry in particular), so it is common to see problems of this type in mathematics competitions.
When I was in junior high, we spent a good deal of time on these puzzles in my language arts class, and I met them again when taking the GRE prior to entering graduate school (the test contains a whole section of them). If you're stumped, check out a solution to the problem.
Vietnamese eight-year-olds do arithmetic
A month later, we heard about a third grade teacher in Vietnam who set the following puzzle for his students. Place the digits from one to nine in this grid, using each only once (the : represents division).
|A puzzle for Vietnamese children. VN Express|
The puzzle above has a similar feel. It's really a question about knowing the order of arithmetic operations (multiplication/division, addition/subtraction, in that order). Beyond that, it just takes trial and error; that is, it's kind of just busy work. Someone who knows some algebra might be able to generate some equations to gain insight into how you might find a solution.
Another approach would be to open up a spreadsheet program and just try all the possibilities. Since there are nine choices for the first box, then eight choices for the second, and so on, there are only (9)(8)(7)(6)(5)(4)(3)(2)(1) = 362,880 possible configurations, of which only a few will give a valid equation. This can be programmed with very little effort.
This article was originally published on The Conversation.