Prodigy is one of the best free sites around for teaching Math by using Game Based Learning. This is an excellent site/game aligned to Common Core Standards for Grades 1st-6th. Teachers everywhere are using Prodigy to assess students through the educational portal that tracks students progress. Also, the game has a unique learning engine which differentiates instruction and helps students w/ problem areas. Being browser based, Prodigy works on any mobile device too.
Below is a demo video...
I highly recommend checking out Prodigy by clicking here!!!
For my Pinterest board on Game Based Learning click here.
*Prodigy is an advertiser of Technology Tidbits.