Dynamic estimation game lets kids design the questions.
Interactive textbook lets kids get hands on with concepts.
Terrific strategy game does a lot with very little.
Fun puzzler with programming skills; some crude humor.
Basic app focuses on visually comparing fractions.
Marble mazes make for fun math practice.
Arcade-style addition practice for kids who like fast games.
Entertaining sim experience requires patience -- or cash.
Hidden instructions hamper fun in video-game company sim.