# International System of Units prefixes

Quantities are measured by values associated with units. These units, when related to the international system of units, can be rewritten in terms of prefixes.

The prefixes have a name, symbol, power of ten and decimal equivalent, as can be seen in the table below.

On a daily basis, we work with several units expressed in terms of prefixes, in which we have as examples the measure of the distance between one city and another, which is almost always expressed in kilometers (km) or the size of some children expressed in centimeters (cm ). In the cited examples we saw a quantity measured by different units, however both are written in function of the prefixes c and k.

The equality between measures that have different units will be exemplified below.

1 km = 1000000 cm

1.10 ^{3} m = 1000000.10 ^{-3} m

1.10 ^{3} m = 1.10 ^{6} .10 ^{-3} m

1.10 ^{3} m = 1.10 ^{3} m

1000 m = 1000 m

We see then that different values can allude to the same measure in which the difference between these values is compensated by the unit.