Here are some apps to practice math.
Website: http://www.khanacademy.org/
Free iPad app: https://itunes.apple.com/us/app/id469863705?mt=8&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/id469863705?mt=8&at=10l6SU
Free Android Phone app: https://play.google.com/store/apps/details?id=org.khanacademy.android
Free Android Tablet app: https://play.google.com/store/apps/details?id=org.khanacademy.android
Edmodo app: https://spotlight.edmodo.com/product/khan-academy,324527/
Website: http://www.ixl.com/
Paid iPad app: https://itunes.apple.com/us/app/motion-math-hd/id410521340?mt=8&uo=4&at=10l6SU
Paid iPhone app: http://itunes.apple.com/us/app/motion-math/id392489333?mt=8&uo=4&at=10l6SU
Edmodo app: http://www.edmodo.com/publisher/motionmath
Free iPad app: http://itunes.apple.com/us/app/motion-math-zoom/id451793073?mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/us/app/motion-math-zoom/id451793073?mt=8&uo=4&at=10l6SU
Free iPad app: http://itunes.apple.com/us/app/motion-math-hungry-fish/id483049169?mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/us/app/motion-math-hungry-fish/id483049169?mt=8&uo=4&at=10l6SU
Paid iPad app: http://itunes.apple.com/us/app/math-games-math-vs-zombies/id470896560?ls=1&mt=8&uo=4&at=10l6SU
Paid iPhone app: http://itunes.apple.com/us/app/math-games-math-vs-zombies/id470896560?ls=1&mt=8&uo=4&at=10l6SU
Paid iPad app: http://itunes.apple.com/us/app/math-bingo-games-a-racing/id415231843?ls=1&mt=8&uo=4&at=10l6SU
Paid iPhone app: http://itunes.apple.com/us/app/math-bingo-games-a-racing/id415231843?ls=1&mt=8&uo=4&at=10l6SU
Paid iPad app: http://itunes.apple.com/us/app/fractions-app/id387434956?mt=8&uo=4&at=10l6SU
Paid iPhone app: http://itunes.apple.com/us/app/fractions-app/id387434956?mt=8&uo=4&at=10l6SU
Website: http://www.sumdog.com/
Paid iPad app: http://itunes.apple.com/us/app/eddys-number-party!-hd/id461063939?mt=8&uo=4&at=10l6SU
Paid iPad app: http://itunes.apple.com/us/app/factor-samurai/id441919897?mt=8&uo=4&at=10l6SU
Paid iPhone app: http://itunes.apple.com/us/app/factor-samurai/id441919897?mt=8&uo=4&at=10l6SU
Google Chrome app: https://chrome.google.com/webstore/detail/ahgfknfdplnpiiiiejiimkojdkjlfmdo
Website: https://www.stmath.com/
Free iPad app: https://itunes.apple.com/us/app/st-math-school-version/id550846820?mt=8&at=10l6SU
Free Android Tablet app: https://play.google.com/store/apps/details?id=air.net.mindresearch.stmath
Free iPad app: http://itunes.apple.com/in/app/tiny-chicken-learns-currency/id511250020?mt=8&uo=4&at=10l6SU
Free iPad app: http://itunes.apple.com/in/app/tiny-chicken-learns-math/id490114227?mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/in/app/tiny-chicken-learns-math/id490114227?mt=8&uo=4&at=10l6SU
Free iPad app: http://itunes.apple.com/us/app/math-games-astro-math-practice/id486756692?mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/us/app/math-games-astro-math-practice/id486756692?mt=8&uo=4&at=10l6SU
Free iPad app: http://itunes.apple.com/in/app/ninja-chicken-tiny-chicken/id503807084?mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/in/app/ninja-chicken-tiny-chicken/id503807084?mt=8&uo=4&at=10l6SU
Free iPad app: http://itunes.apple.com/us/app/sas-flash-cards/id364784968?mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/us/app/sas-flash-cards/id364784968?mt=8&uo=4&at=10l6SU
Paid iPad app: https://itunes.apple.com/us/app/math-monsters/id499455175?ls=1&mt=8&uo=4&at=10l6SU
Website: http://aprendagames.com/games/math-monsters/flash-game/
Paid iPad app: https://itunes.apple.com/us/app/math-bingo/id371338715?mt=8&uo=4&at=10l6SU
Paid iPhone app: https://itunes.apple.com/us/app/math-bingo/id371338715?mt=8&uo=4&at=10l6SU