For centuries, students have learned that in a right triangle, the square of the hypotenuse equals the sum of the squares of the other two sides. Known as the Pythagorean Theorem, this ...

Counting will get you nowhere. Try a little combinatorics instead. By Kenneth Chang A couple of weeks ago, I wrote about a viral math problem — 8÷2(2+2) = ? — that drew the disdain of many ...