Poor Robert! Math was a nightmare for him...until the Number Devil popped into his dreams and showed him a whole new way to understand math concepts. Over the course of 10 amazing nights, the witty Number Devil helps Robert discover the tricks and wonders of numbers by magically transforming unfamiliar or difficult math concepts into a dynamic learning experience. Join Robert and the Number Devil and learn as you play the Number Devil way, where some numbers "hop," prime numbers are "prima donnas," and roots are "rutabagas!" Who knew math cold be so devilishly fun?