Answer
$\frac{1}{12}$
Work Step by Step
$\frac{7}{30}-\frac{3}{20} $
The LCD is 60
$\frac{7}{30}\times\frac{2}{2}-\frac{3}{20}\times\frac{3}{3}$
$\frac{14}{60}-\frac{9}{60}$
$\frac{14-9}{60}$
$\frac{5}{60}$
Simplify
$\frac{1}{12}$