Number Patterns and + -

Crack the Safe
http://pbskids.org/cyberchase/webisode_1/web_2game.html

Island Race Subtraction
http://www.arcademicskillbuilders.com/games/island_chase/island_chase.html

Speed Subtraction Challenge
http://www.oswego.org/ocsd-web/games/SpeedGrid/Subtraction/urikasub1res.html

Subtraction Bowling
http://www.abc.net.au/countusin/games/game8.htm

Alien Addition
http://www.arcademicskillbuilders.com/games/alien/alien.html