$a)7-1\frac{3}{5}=6-\frac{3}{5}=5\frac{2}{5}$

$b)5-2\frac{1}{4}=3-\frac{1}{4}=2\frac{3}{4}$ $b)5-2\frac{1}{4}=3-\frac{1}{4}=2\frac{3}{4}$

$c)7-3\frac{3}{7}=4-\frac{3}{7}=3\frac{4}{7}$

$d)8-3\frac{1}{9}=5-\frac{1}{9}=4\frac{8}{9}$

$e)12-7\frac{3}{8}=5-\frac{3}{8}=4\frac{5}{8}$

$f)20-13\frac{8}{11}=7-\frac{8}{11}=6\frac{3}{11}$