A maths and thinking skills site with hundreds of word puzzles to ponder over. Perfect for lesson warm ups and improving mental maths.
http://ictmagic.wikispaces.com/Maths
SUPERB! Place the numbers on the number line. Loads of levels. Negative numbers and decimals. Play against the clock for a score. My class's favourite warm up, useful throughout school from year 3 to year 6.