The following websites gives little mini arithmetic papers, this supports pupils mental maths knowledge (just like the ones they have practiced in class!)
Again BBC bitesize is always a good starting point for revision.
We also see that it is essential that pupils see the utility in maths. This website provides some great practical activities that you and your child can complete together, which will support your child to develop a concrete understand of the maths concepts applied.
Finally, NRICH provides some great maths challenges, to encourage your child to think critically and logically when approaching mathematical problems.