The numerical value always precedes the unit, and a space is always used to separate
the unit from the number. Thus the value of the quantity is the product of the number
and the unit, the space being regarded as a multiplication sign (just as a space
between units implies multiplication). The only exceptions to this rule are for the unit
symbols for degree, minute, and second for plane angle, °, ′, and ″, respectively, for
which no space is left between the numerical value and the unit symbol.