

The metric system consists of base units, modified by prefixes that increase or decrease the unit value by factors divisible by 10. There are different base units for each type of measurement. For example, gram for measuring mass, metre for measuring distance and joule for measuring work. However, sometimes the base units are too small or too large to easily describe the measurement. This is when it is useful to scale the base units, using the prefixes. For example, the metre is a good unit for measuring the dimensions of a house, but not for calculating distances between cities. In this case, we prefer to use kilometres, each of which is 1000 metres. Larger Unit Prefixes:These prefixes form units that are larger than the base unit:
Smaller Units:These prefixes form units that are smaller than the base unit:

