Решить примеры по действиям

А)
$1)3 \frac{11}{21}-2 \frac{4}{15}=3 \frac{11*5}{3*7*5}-2 \frac{4*7}{3*5*7}= 3 \frac{55}{105}-2 \frac{28}{105}=1 \frac{55-28}{105}= \\ \\ 1 \frac{27}{105}=1 \frac{9}{35} = \frac{44}{35} \\ \\ 2)13.2: \frac{44}{35}= \frac{132}{10}* \frac{35}{44}= \frac{3*44}{2*5}* \frac{5*7}{44}= \frac{21}{2}=10.5 \\ \\ 3 ) 14-10.5=3.5$

б)
$1)6 \frac{11}{15}-4 \frac{3}{20}= 6 \frac{11*4}{15*4}-4 \frac{3*3}{20*3}=6 \frac{44}{60}-4 \frac{9}{60}=2 \frac{44-9}{60}=2 \frac{35}{60}=2 \frac{7}{12}= \frac{31}{12} \\ \\ 2)18.6: \frac{31}{12}= \frac{186}{10}* \frac{12}{31}= \frac{6*31}{10}* \frac{12}{31}=72 \\ \\ 3)20-72=-52$