These are the math apps I have used with my kids.
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
Paid Android Phone app: https://play.google.com/store/apps/details?id=com.wewanttoknow.DragonBoxPlus
Paid iPad app: https://itunes.apple.com/us/app/dragonbox-algebra-5+/id522069155?mt=8&at=10l6SU
Paid iPhone app: https://itunes.apple.com/us/app/dragonbox-algebra-5+/id522069155?mt=8&at=10l6SU
Paid Mac program: https://itunes.apple.com/us/app/dragonbox-algebra-5+/id524967552?mt=12&at=10l6SU
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
Paid iPad app: https://itunes.apple.com/us/app/king-of-math-junior/id579528355?mt=8&uo=4&at=10l6SU
Paid iPhone app: https://itunes.apple.com/us/app/king-of-math-junior/id579528355?mt=8&uo=4&at=10l6SU
Free iPad app: https://itunes.apple.com/us/app/king-of-math-junior-free/id605752286?mt=8&uo=4&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/king-of-math-junior-free/id605752286?mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/us/app/mermaid-waters-adventures/id454136246?mt=8&uo=4&at=10l6SU
Paid iPad app: https://itunes.apple.com/us/app/montessori-numbers-for-kids/id547209737?ls=1&mt=8&uo=4&at=10l6SU
Paid iPhone app: https://itunes.apple.com/us/app/montessori-numbers-for-kids/id547209737?ls=1&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
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
Free iPad app: http://itunes.apple.com/us/app/math-workbook/id467548534?mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/us/app/math-workbook/id467548534?mt=8&uo=4&at=10l6SU