Measurement is integral to analytical chemistry. Each record comprises a number – denoting the magnitude – and the unit – a standard for comparison. Different units can be used to express the same measurement of an object. So, for worldwide consistency, a standardized system of units is accepted, known as Système International d'Unités or SI units. SI units for quantities such as mass, distance, temperature, time, electric current, luminous intensity, plane angle, solid angle, and amount of a substance are called fundamental units. Other SI-derived units are a product of multiple fundamental units or a product of units with constants. Some non-SI units are also widely used along with SI units. However, the quantities in these units can be interconverted into SI units. To express large or small quantities in a simplified form instead of exponential notations, prefixes are added to the SI units.