There is certainly not any shortage of free mathematics games on the web, but sorting through them all to find the ones that address your curriculum goals can be time-consuming. That’s when sites like Math Chimp can be helpful. Math Chimp is a catalog of more than one hundred online mathematics games for elementary school students. Teachers can find games on Math Chimp by selecting the grade that they teach then selecting a standard or objective. After you make those selections Math Chimp will direct you to an appropriate mathematics game for your students.

If you like Math Chimp, here are some other math resources you might want to explore:
Ghost Blasters, Math Blasters
Interactive Algebra
Arcademic Math Games
11 Mathematics Resources to Try in 2011