Rounding Numbers

http://www.topmarks.co.uk/Flash.aspx?f=DartboardRoundingv2

http://www.mathnook.com/math/alien-math-rounding-nearest-100.html

http://www.mathnook.com/math/bike-racing-math-rounding.html

http://www.mathnook.com/math/alien-math-rounding-nearest-10.html