Algebra websites

http://www.math-play.com/Two-Step-Equations-Game.html

http://www.xpmath.com/forums/arcade.php?do=play&gameid=64

http://www.quia.com/ba/143047.html

Horizon math

Integers:

http://www.sheppardsoftware.com/mathgames/integers/FS_Integer_addition.htm

http://www.mathplayground.com/ASB_OrbitIntegers.html

http://www.math-play.com/Integers-Jeopardy/Integers-Jeopardy.html

Probability

https://www.mathsisfun.com/data/probability.html

http://spreadsheets.about.com/od/excelcharts/ss/bar_graph.htm#step-heading