http://www.sheppardsoftware.com/mathgames/money/mathman_money_round.htm
http://www.sheppardsoftware.com/mathgames/round/mathman_round_thousands.htm
http://education.abc.net.au/res/i/L1930/index.htmlÂ
http://www.sheppardsoftware.com/mathgames/decimals/scooterQuestDecRound.htm