One site you may want to look at is BBC bitesize.
This is the Key Stage 2 site covering primary school maths. http://www.bbc.co.uk/...ent_fractions/read/1/
You can also look at key Stage 3 if you wish.
The best site is this one but apart from a few samples you need a subscription, although if you have a child at school they may have a logon you can use
http://www.mymaths.co.uk/
If you can suggest some specific topics I'll try to find a good site for you