Rounding Whole Numbers:
http://www.aaamath.com/g32_rox1.htm
http://www.funbrain.com/tens/index.html
http://www.ixl.com/math/grade-5/rounding
Rounding Decimals:
http://www.sheppardsoftware.com/mathgames/decimals/scooterQuestDecRound.htm
http://eclassroom.110mb.com/Games/5th%20Math/Decimals1.swf
http://www.free-training-tutorial.com/decimal/decimal-sharks.html