http://www.math-play.com/One-Step-Equation-Game.html
http://www.math-play.com/soccer-math-one-step-equations-game/one-step-equations-game.html
http://www.xpmath.com/forums/arcade.php?do=play&gameid=105
http://www.quia.com/quiz/640482.html?AP_rand=179254155
https://www.mangahigh.com/en-us/games/algebrameltdown
http://passyworldofmathematics.com/equations-games/
