Quantitats

Quantitats, in many scientific and technical contexts, are properties that can be measured or computed and expressed as a magnitude together with a unit. Quantitats enable comparison, specification, and calculation, and they may refer to physical attributes such as length or mass, or to abstract attributes in mathematics or economics.

Quantitats are classified by how their magnitude is described: scalar quantitats have only magnitude, while vector quantitats also include a direction. Some quantitats are fundamental, defined by a system of units, while others are derived from these base quantitats, such as speed (distance per time) or force (mass times acceleration).

In the International System of Units (SI), seven base quantitats define the base units: length (metre), mass (kilogram), time (second), electric current (ampere), thermodynamic temperature (kelvin), amount of substance (mole), and luminous intensity (candela). All other quantitats are derived from these base quantitats and carry corresponding derived units and dimensions.

Measurement and calculation with quantitats require attention to units and uncertainties. Quantitats have numerical values whose precision is expressed by significant figures or confidence intervals. Dimensional analysis uses the units and dimensions of quantitats to check the consistency of equations and calculations across disciplines.