Young kids learn math by playing with toys that demonstrate the concepts, bringing abstract descriptions to life. That’s why teachers like manipulatives, like base ten blocks, to help teach core concepts. Motion Math Zoom ($2.99, plus additional in-app purchases, on iPhone, iPad touch, or iPad) turns that idea into a game that illustrates hard-to-grasp concepts like negatives and decimals. Kids have to understand how .01 is different from 1 and .1 to score and move on in the game. Just playing the game illustrates the concepts, letting kids learn through trial and error. Kids can play at their own pace, or you can amp up the pressure by turning on “The Needle” to impose a little time pressure.