Dimensional analysis

A conceptual tool often applied in mathematics, physics, chemistry, and engineering to assure that the units in an equation are consistent; that the right-hand side of an equation can indeed be equated to the left side. In the equations, for example: velocity= distance/ time, the units of velocity on the left side are feet per second, and on the right, the units of distance are feet and time, seconds, so the units on both sides of the equation are the same.