There are loads of great sites out there to help you with your maths - some of the best are mentioned below. If you have any others that you'd like to recommend, let me know... house points are guaranteed!
Don't forget that whilst we tend to use this site for homework, there are loads of lessons (look for the little board symbol) and games on most aspects of the curriculum
BBC Bitesize - Maths
BBC Bitesize has been around for years and it's recently been updated. It's packed with some great advice on maths including games, tutorials and videos, Highly recommended!
Woodland's Junior Maths Pages
Woodland's Junior is a school that has a brilliant website with loads of advice and help in every subject. Their maths pages are packed with lots of advice and help that I'm sure you'll find useful if you're struggling.
This brilliant blog gives loads of advice about how to do anything mathematical - all the way to GCSE. Some of the lessons are not relevant to KS2, but an awful lot are! There are also some great problem pages that you can use to test your skills
Lots of great games to help you with your maths, many of them with clear graphics and explanations to help you understand anything that you're finding challenging!
IXL lists all of the aspects of maths taught in year 6 and asks you questions to assess your understanding. If you get one wrong, read the explanation about how you should have done it and you'll teach yourself to be a maths wizz in no time!