2.169. Вычислите: а) \(\frac{23}{24}-\left(\frac{1}{6}+\frac{1}{4}\right)\); б) \(\frac{4}{35}+\left(\frac{3}{5}-\frac{4}{7}\right)\); в) \(\frac{11}{15}-\left(\frac{2}{3}-\frac{3}{20}\right)\); г) \(\frac{5}{18}+\left(\frac{2}{9}+\frac{1}{27}\right)\).

а)

\(\frac{1}{6}+\frac{1}{4}=\frac{2}{12}+\frac{3}{12}=\frac{5}{12}=\frac{10}{24}\).

\(\frac{23}{24}-\frac{10}{24}=\frac{13}{24}\).

б)

\(\frac{3}{5}-\frac{4}{7}=\frac{21}{35}-\frac{20}{35}=\frac{1}{35}\).

\(\frac{4}{35}+\frac{1}{35}=\frac{5}{35}=\frac{1}{7}\).

в)

\(\frac{2}{3}-\frac{3}{20}=\frac{40}{60}-\frac{9}{60}=\frac{31}{60}\).

\(\frac{11}{15}-\frac{31}{60}=\frac{44}{60}-\frac{31}{60}=\frac{13}{60}\).

г)

\(\frac{2}{9}+\frac{1}{27}=\frac{6}{27}+\frac{1}{27}=\frac{7}{27}\).

\(\frac{5}{18}+\frac{7}{27}=\frac{15}{54}+\frac{14}{54}=\frac{29}{54}\).

Ответ: а) \(\frac{13}{24}\); б) \(\frac{1}{7}\); в) \(\frac{13}{60}\); г) \(\frac{29}{54}\).