In the Natural Units environment, the equality and inequality operators (=, <, <=, >, >=, and <>) are modified so that they perform the necessary operations on expressions with units.

The properties of the five arithmetic operations are:

where a and b are units; A and B are coefficients; and r is the conversion factor from the unit $b$ to the unit a.

with(Units[Natural]):

3*ft=yd;

$3=3$

evalb((1));

$\mathrm{true}$

1.60*m < mi;

$1.60<\frac{201168}{125}$

evalb((3));

$\mathrm{true}$

30.48*cm = ft;

$30.48=\frac{762}{25}$

evalb((5));

$\mathrm{true}$

3 * ft + 3*`in` = m;

$\frac{4953}{5000}=1$

evalb((7));

$\mathrm{false}$