With Didj Custom Gaming System, you can sharpen your math and spelling skills and save the world all at the same time. Didj is the first-ever handheld gaming device that allows users to customize games to incorporate learning. Have a multiplication quiz next week? Just input times tables into one of nine learning games, like SpongeBob SquarePants: Fists of Foam. Solve the problems correctly and not only will you win the game, but you’ll learn something, too.