The video above contains an explanation of the metric system, including a definition of the prefixes.
The above video shows one way to convert from one metric unit to another, such as how to convert metres to centimetres.
This video shows another way to convert between metric units.
The metric system was introduced in France in the late 1700's.
The metric system is not more accurate than the "imperial" system used in America, but it is considered to be much easier to use.
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