Use GCF and LCM to help with fractions for simplifying or finding a common denominator. There are 2 game links included in the video. I am including the links. You may need to copy and paste the link into the address bar.
http://www.fun4thebrain.com/beyondfacts/lcmsnowball.html
http://www.sheppardsoftware.com/mathgames/fractions/GreatestCommonFactor.htm