An easy way to remember metric conversions is by remembering that "King Henry Doesn't Understand Doing Conversions of Metric." Here K, H, D, U, D, C and M stand for kilo, hecto, deka, unit, deci, centi and milli, respectively, giving values from the biggest to the smallest.
Kilo, hecto, deka, unit, deci, centi and milli have numerical values of 1,000, 100, 10, 1, 0.1, 0.01 and 0.001, respectively. Since 10s form the basic of the metric system, remembering the aforementioned items make conversion easy. Unit refers to gram, meter and liter. For example, 1 kilometer is equivalent to 1,000 meters.
Gram is the basic unit of measurement for mass or weight. Liquid volume is measured in liters. The basic unit of measurement for length is meter.