Khan Academy
Khan Academy: Metric Units of Length Review
Metric units of length (millimeters, centimeters, meters, and kilometers) are reviewed and practice problems are provided.
ABCya
Ab Cya: Strolling With My Gnomies, a Measuring Game
Decide whether you want to measure in Standard or metric and at what level (i.e. inch, half inch or centimeter, millimeter) and begin practice. Computer will generate a line above the ruler and the player enters the length and checks for...