In this magic square game you have to move the numbers on the right inside the squares, so that the sum of any three numbers vertically, horizontally, or diagonally equals to 15.
Want to test your mathematical knowledge? Khan Academy has some mind bending riddles and puzzles. The content is produced by people in the math field (tutors, teachers, professors, etc...) and is peer-reviewed.
GeoGebra is dynamic mathematics software for all levels of education that brings together geometry, algebra, spreadsheets, graphing, statistics and calculus in one easy-to-use package.