Brrriiiing! Recess time! Little chimps Jill and Jake find more than just their favorite games in the schoolyard today. They also discover the important mathematical concept of doubling, or adding a number to itself. Easy to learn and fun to memorize, doubling is a valuable problem-solving tool that helps kids prepare for multiplication. A must-have addition to any math-themed picture book library, Double Play makes this arithmetic lesson as welcome as recess.