https://mathsframe.co.uk/

Although this is a subscription site – you can access many of the games to practice different areas of maths for free.

Helpfully free games and the games that will work on tablets are listed separately.

http://www.ictgames.com/mobilePage/index.html

This site has a variety of games to practice different areas of maths.

http://mathszone.co.uk/

This is a collection of lots of different games – some of which are from the other sites listed here.

https://www.topmarks.co.uk/

This site includes different subjects. The maths games and activities are good for practising number knowledge such as times tables as well as addition and subtraction facts.