BBC has a selection of videos explaining maths concepts:
WebLink: http://www.bbc.co.uk/education/

Nrich has a range of maths games, problems and articles on all areas of maths. Parents of Key Stage 1 children should select ‘stage 1’ and parents of Key Stage 2 children should select ‘stage 2’:
WebLink: http://nrich.maths.org/

Oxford Owl includes a range of activities, top tips and eBooks to help your child with their maths at home:
WebLink: http://www.oxfordowl.co.uk/maths-owl/

A Maths Dictionary for Kids is a great online maths dictionary, which contains hundreds of definitions, as well as animations and activities to help bring maths words to life:
WebLink: http://www.amathsdictionaryforkids.com/

WebLink: http://www.crickweb.co.uk/ks1numeracy
WebLink: http://www.crickweb.co.uk/ks2numeracy
WebLink: http://www.mathsisfun.com/games/
WebLink: http://www.ictgames.com/resources
WebLink: http://mathszone.co.uk/
WebLink: http://www.topmarks.co.uk/maths-games
WebLink: http://mathsframe.co.uk/resources/