Get your timer out and see whether you can remember the golden rule from grade school math class.

(cheerful music) (spring boings) (glass squeaks) - [Children] Math Mights! - Welcome back, third grade Math Might friends. It's me, Ms. Askew, here again. Are you ready to have some fun with math?

Grade school math students are likely familiar with teachers admonishing them not to just guess the answer to a problem. But a new proof establishes that, in fact, the right kind of guessing is ...