Срочно помогите!!!3 столбик.

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$\frac{11}{20}- \frac{5}{12}= \frac{33}{60}- \frac{25}{60}= \frac{8}{60}= \frac{2}{15} \\ \frac{8}{9}+ \frac{7}{54}= \frac{48}{54}+ \frac{7}{54}= \frac{55}{54}=1 \frac{1}{54} \\ \frac{5}{6}- \frac{17}{21}= \frac{35}{42} - \frac{34}{42}= \frac{1}{42} \\ \frac{3}{16}+ \frac{1}{24}= \frac{18}{96}+ \frac{4}{96}= \frac{22}{96}= \frac{11}{48} \\ \frac{5}{6}- \frac{22}{27}= \frac{45}{54} - \frac{44}{54}= \frac{1}{54} \\$
$\frac{7}{25}- \frac{4}{15}= \frac{21}{75}- \frac{20}{75} = \frac{1}{75} \\ \frac{3}{10}+ \frac{1}{6} = \frac{9}{30}+ \frac{5}{30} = \frac{14}{30}= \frac{7}{15} \\ \frac{2}{5}- \frac{11}{30}= \frac{12}{30}- \frac{11}{30} = \frac{1}{30} \\ \frac{3}{8}+ \frac{7}{20}= \frac{15}{40}+ \frac{14}{40} = \frac{29}{40} \\ \frac{1}{6}- \frac{1}{7}= \frac{7}{42}- \frac{6}{42} = \frac{1}{42}$