In contrast to pure mathematics, in the natural sciences such as chemistry and physics, and in engineering, we use units in addition to quantities. We need to distinguish units from variables.
Let's take a sample. We shall write a formula that multiplies the speed s of one meter per second by the factor m. A straightforward way of doing this could be like so:
\( m \cdot s = m \cdot 1 m s^{-1} \)The LaTeX standard output would be:
What on earth? It's pretty tempting to mathematically simplify the right side, which could be interpreted as square meters per second or as millimeters per second. Or multiply both sides by s, which may mean speed (s) or seconds. Units and variables look very similar. Furthermore, our space between 1 and m has been lost. For smart writing that fits common standards, we may require the following: