iKnowthat.com has multimedia educational games for kids ages 2-12.

Leon's Math Dojo Game

Kids can become black belts in math with Leon the Chameleon! Leon's Math Dojo is a fun, multimedia arcade style game in which kids answer arithmetic problems during timed rounds. Math problem sets include counting, skip counting, one-digit addition, two-digit addition, one-digit subtraction, two-digit subtraction, multiplication, two-digit by one-digit multiplication, and division. There is also an untimed practice option.

This game helps kids learn math facts and build mental computation skills.