http://www.businessinsider.com/pisa-worldwide-ranking-of-mat...
> I didn't define useful either:
> but if you can understand written instructions it doesn't matter what you happened to read to get that skill.
Of course you are free to define useful in a way that makes it impossible to argue or to have a discussion. So let's stick to the way it is defined for the purpose of say University admission.
> Why is reading a classic American author important?
Reading difficult work earlier develops higher reading comprehension faster.
> Likewise, what is wrong with using M&Ms for learning math?
I think if by 4th grade you still need concrete pieces to understand integers or denominators of a fraction or whatever they were supposed to represent, that is a sign of a weak math education. In general concrete examples are antithetical to learning advanced math, this leads do the monkey-style ability to solve problems that are similar ones presented in textbooks, but not the ability to reason effectively about an unfamiliar problems.