fraction minus problem

$\frac{11}{12} - \frac{8}{9}$

Get a common denominator:

$\frac{11(3)}{12(3)} - \frac{8(4)}{9(4)} \\~\\ \frac{33}{36)} - \frac{32}{36}$

Subtract:

$\frac{33}{36)} - \frac{32}{36} = \frac{1}{36}$