$a)\frac{5}{12}-\frac{4}{24}=\frac{10}{24}-\frac{4}{24}=\frac{6}{24}=\frac{1}{4}$

$\frac{3}{4}-\frac{3}{5}=\frac{15}{20}-\frac{12}{20}=\frac{3}{20}$

$\frac{4}{5}-\frac{11}{15}=\frac{12}{15}-\frac{11}{15}=\frac{1}{15}$ $\frac{4}{5}-\frac{11}{15}=\frac{12}{15}-\frac{11}{15}=\frac{1}{15}$

$\frac{5}{6}-\frac{3}{8}=\frac{20}{24}-\frac{9}{24}=\frac{11}{24}$

 

$b)2\frac{3}{10}-\frac{1}{15}=2\frac{9}{30}-\frac{2}{30}=2\frac{7}{30}$

$3\frac{1}{2}-\frac{4}{13}=3\frac{13}{26}-\frac{8}{26}=3\frac{5}{26}$

$1\frac{5}{6}-\frac{2}{3}=1\frac{5}{6}-\frac{4}{6}=1\frac{1}{6}$

$7\frac{9}{14}-7\frac{4}{7}=7\frac{9}{14}-7\frac{8}{14}=\frac{1}{14}$

 

$c)3\frac{1}{4}-2\frac{1}{3}=3\frac{3}{12}-2\frac{4}{12}=2\frac{15}{12}-2\frac{4}{12}=\frac{11}{12}$

$4\frac{1}{9}-2\frac{2}{3}=3\frac{10}{9}-2\frac{6}{9}=1\frac{4}{9}$

$3\frac{1}{10}-1\frac{2}{15}=3\frac{3}{30}-1\frac{4}{30}=2\frac{33}{30}-1\frac{4}{30}=1\frac{29}{30}$

$7\frac{1}{4}-3\frac{7}{8}=7\frac{2}{8}-3\frac{7}{8}=6\frac{10}{8}-3\frac{7}{8}=3\frac{3}{8}$