Commonsense.org has a browseable collection of reviews by teachers for teachers of Math apps, games and websites to help you find and use new resources.

PhET interactive simulations by the University of Colorado give students hands on activities to explore the concepts behind math.

Math Playground provides a whole toolkit of interactive maths resources.

Topmarks has resources for various age groupings including spinners and timers and number lines. They also provide free resources for Interactive Whiteboards.

Desmos teacher offers free online activites that you can assign to yoru students as a class or individually.

Mathslinks is a site created by a NSW Math teacher to share resources and activities by other NSW teachers.