Addition/ Subtraction

Arithmetic Four
http://www.shodor.org/interactivate/activities/agame/index.html

Batter Up Baseball
http://www.prongo.com/math/index.html

Base Blocks: Subtraction
http://matti.usu.edu/nlvm/nav/frames_asid_155_g_2_t_1.html

Addition Sums 10-18
http://www.quia.com/jg/65611.html

Seashell Search
http://www.hbschool.com/activity/seashell_search/index.html

Froggy Hops
http://atschool.eduweb.co.uk/toftwood/frog.html

Addition Surprise
http://www.harcourtschool.com/activity/add/add.html

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

Soccer Shootout
http://onlineintervention.funbrain.com/cgi-bin/shtml.cgi?A1=../fractop/index.html

Addition Level I Sums 0-9
http://www.quia.com/jg/65807.html

Day at the Beach Subtraction
http://www.hbschool.com/activity/day_at_beach/

Target Take Away
http://atschool.eduweb.co.uk/toftwood/targettakeaway.html

Math Dojo
http://www.iknowthat.com/com/L3?Area=Dojo

Subtraction Sum Sense
http://www.oswego.org/ocsd-web/games/SumSense/sumsub.html

Addition Concentration
http://www.aplusmath.com/Games/Concentration/Addition_Concentration.html

Math Journey
http://www.quia.com/mathjourney.html

Fun with Fireflies Subtraction
http://www.hbschool.com/activity/fireflies/index.html

Adding 9 Fairy
http://atschool.eduweb.co.uk/toftwood/fairy2.html

Cyberbee Challenge -Select Addition or Subtraction
http://www.mathmastery.com/cyberchallenge/

Subtracting Three Digits
http://www.harcourtschool.com/activity/elab2002/grade_3/004.html

Tic Tac Toe Math Squares
http://www.funbrain.com/tictactoe/index.html
Addition and Subtraction Battleship Game
http://www.quia.com/ba/37104.html

Mad Minutes On the Web
http://www.sadlier-oxford.com/math/mathgames/mad_minute_game/navigation3.htm

Rainforest Maths
http://rainforestmaths.com/