http://www.ixl.com/math/grade-3
http://www.coolmath4kids.com/
http://jmathpage.com/
http://www.funbrain.com/brain/MathBrain/MathBrain.html
http://www.aaamath.com/grade3.htm
http://www.primarygames.com/math/grade/grade3-math-games.php
http://www.mathplayground.com/
http://multiplication.com
http://www.softschools.com/math/games/