In general, a unit is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Units are used to measure physical quantities that need clear definitions to be useful, and a standard system of units facilitates reproducibility of experimental results, which is central to the scientific method.
In mathematics, a unit can refer to the rightmost position in a number or the ones place. For example, in the number 6713, 3 is the units number. A unit may also refer to the standard units used for measurement, such as meters, liters, or seconds.
There are different types of units, including base units, derived units, and supplementary units. Base units are the fundamental units of measurement, such as the meter, kilogram, and second. Derived units are obtained by combining base units, such as the newton (kgm/s^2) or the joule (kgm^2/s^2). Supplementary units are used to measure angles, time, and other quantities that are not part of the International System of Units (SI) .
