A numerical-value equation is an equation between

quantities Quantity or amount is a property that can exist as a multitude or magnitude, which illustrate discontinuity and continuity. Quantities can be compared in terms of "more", "less", or "equal", or by assigning a numerical value multiple of a unit ...

in which just the values of the quantities occurs but not the

unit of measurement A unit of measurement is a definite magnitude (mathematics), 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. Any other quantity of that kind can ...

. Therefore, the

equation In mathematics, an equation is a formula that expresses the equality of two expressions, by connecting them with the equals sign . The word ''equation'' and its cognates in other languages may have subtly different meanings; for example, in ...

requires to be used with the values the quantity has in a specific unit. A numerical value equation always has to be marked as such. Numerical value equations are in contrast to quantity equations. Quantity equations hold independently of the unit used to express the value of the quantity. For example, a quantity equation for

displacement Displacement may refer to: Physical sciences Mathematics and Physics *Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object). The actual path ...

''d'' as

speed In everyday use and in kinematics, the speed (commonly referred to as ''v'') of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quanti ...

''s'' multiplied by time difference ''t'' would be: :''d''=''s'' ''t'' for ''s''=5m/s and ''t'' and ''d'' in any units. In contrast, a numerical-value equation would be: :''D''=5 ''T'' for ''T'' in seconds and ''D'' in metres. Generally, the use of numerical value equations is discouraged.

References

{{Reflist Physical quantities

See also

References