Exploring maths apps today - the ones below are ideal for consolidating fractions, angles, area, tessellation, 2D shapes and symmetry work. If we're ticking boxes then it's also a winner for ICT and art.
But who cares about that when you can make cool patterns?
http://www.mathlearningcenter.org/web-apps/geoboard/
http://www.mathlearningcenter.org/web-apps/pattern-shapes/
