The best way to teach mathematics to children is via games. An example: ArithmeTick, a game that teaches children to add, subtract, multiply and divide. Children are motivated because the faster and more accurate they are with these mathematical operations, the higher the score they get.
The program includes four difficulty levels, and examples of exercises to do. And to count the time used, ArithmeTick includes a chronometer. For each correct answer, the player gains extra seconds, all in a fun and practical interface.