I think proving the sqrt(2) is irrational is great. That was the very first question on my first college math homework assignment. It's a great way to weed out

I think proving the sqrt(2) is irrational is great. That was the very first question on my first college math homework assignment. It's a great way to weed out people aren't even close to the level they should be at math-wise. Don't worry that others can do it. FizzBuzz can also be cargo-culted. FizzBuzz tells you nothing about how good someone is, but can tell you a lot about how bad they are. I would also suggest this: Prove exp(pi*i)+1=0.