DragonBox Numbers - Teach kids about numbers with an easy and fun game
Sum Fun - A fun number puzzle game for iPhone and iPad.
Wikids - An encyclopedia that talks to your kids
Sum - Simple Maths Puzzle - How fast can you add two numbers?
Litnerd - The Pixar for education, reading program for K-5 schools
Griddition - Griddition is a challenging numbers puzzle where you must fill a grid with numbers, Sudoku-style.