Revise Wise Maths
http://www.bbc.co.uk/schools/ks2bitesize/maths

AAA Math (basics - drill)
http://www.aaamath.com

A Plus Math (drill and games - basics)
http://www.aplusmath.com

Rain Forest Maths (through 7th grade)
http://www.rainforestmaths.com

Math.com

Quai Shared Activities