Rounding
Follow these links to practise rounding numbers.
Rounding to the nearest 10
http://www.janbrett.com/piggybacks/rounding.htm
To the nearest 10, 100, 1000
http://www.bbc.co.uk/skillswise/numbers/wholenumbers/whatarenumbers/rounding/quiz.shtml
http://www.softschools.com/math/practice/rounding_numbers.jsp
Try the ’super brain’ level for a real test of your mathematical skills
http://www.funbrain.com/tens/index.html