Math Measurement: metric conversion

http://www.sheppardsoftware.com/mathgames/measurement/MeasurementMeters.htm
http://www.bbc.co.uk/skillswise/game/ma22leng-game-build-a-shed
http://mrnussbaum.com/soup/
http://ca.ixl.com/math/grade-6/convert-and-compare-metric-units
http://www.mathfox.com/mathgames/metric-system-game/