The metric system, originating in France in 1791, is the current international standard for measurements. In common use, there are three units that are frequently used in the metric system:
- Meter (m) - a unit of length
- Gram (g) - a unit of mass
- Liter (L) - a unit of weight
The two tangible units, meter and gram, can be converted to larger and smaller representations simply by multiplying by 10.
Meter
A meter is the standard unit of length; it is approximately equal to 39.37 inches (3.28 feet) in the US customary system.
A normal meter stick will have 10 divisions, each representing 1 decimeter (dm). This is further divided by 10 to give a total of 100 centimeters (cm), and then by ten again to give 1000 millimeters (mm).
1000 meters equals 1 kilometer (km).
In the UK a meter is known as a "metre".
Gram
The gram is a unit of mass. It is commonly used to state weights as well.
There are 1000 grams in a kilogram (kg).
1000 kilograms is equal to 1 tonne (t).
A milligram (mg) is 1/1000th of a gram. Milligrams are often used in medicine and chemistry.
Liter
The liter (L) is a unit of liquid volume, equal to a cube of water measuring 10cm * 10cm * 10cm. A milliliter (mL) is equal to one cubic centimeter.