Decimals in measuring units - introduction
We study simple conversions between metric measuring units that are based on the conceptual understanding of decimals. For example, since we know that 0.001 (one-thousandth) of a meter is a millimeter, then 5 millimeters means 5 thousandths of a meter, and as a decimal is written 0.005 m.
Another example. The prefix "centi" basically means one hundredth. So, 6 centiliters literally means 6 hundredths of a liter, or 0.06 L.
So, this understanding of decimal place value gives us an easy means of converting quantities expressed in derived units back to the basic unit (such as meter, liter, or gram).
See also
Basics of the metric system and the prefixes