### Theory:

Unit prefixes are the symbols placed before the symbol of a unit to specify the order of magnitude of the quantity.
They are useful to express very large and very small quantities.
Example:
$$k$$ ($$kilo$$) is the unit prefix in the unit, $$Kilometre$$.
A unit prefix stands for a specific positive or negative power of 10. Some unit prefixes are given in the table.

 Power of 10 Prefix Symbol ${10}^{15}$ peta P ${10}^{12}$ tera T ${10}^{9}$ giga G ${10}^{6}$ mega M ${10}^{3}$ kilo k ${10}^{2}$ hecto h ${10}^{1}$ deca da ${10}^{-1}$ deci d ${10}^{-2}$ centi c ${10}^{-3}$ milli m ${10}^{-6}$ micro $\mathrm{\mu }$ ${10}^{-9}$ nano n ${10}^{-12}$ pico p ${10}^{-15}$ femto f

Unit Prefixes