Ответ:

а) \( -1\frac{3}{5}=-\frac{8}{5} \).

\(\frac{2}{5}:\left(-\frac{8}{5}\right)=\frac{2}{5}\cdot\left(-\frac{5}{8}\right)=-\frac{1}{4}\).

б) \( -2\frac{2}{9}=-\frac{20}{9} \).

\(-\frac{5}{6}:\left(-\frac{20}{9}\right)=\frac{5}{6}\cdot\frac{9}{20}=\frac{3}{8}\).

в) \(-3\frac{1}{3}=-\frac{10}{3}\).

\(-\frac{10}{3}:2=-\frac{10}{3}\cdot\frac{1}{2}=-\frac{5}{3}=-1\frac{2}{3}\).

г) Сначала вычислим выражение в скобках:

\(1\frac{2}{5}+2\frac{1}{3}=\frac{7}{5}+\frac{7}{3}=\frac{56}{15}\).

\(1\frac{3}{4}\cdot\frac{56}{15}=\frac{7}{4}\cdot\frac{56}{15}=\frac{98}{15}\).

\(\frac{98}{15}:1\frac{5}{9}=\frac{98}{15}:\frac{14}{9}=\frac{98}{15}\cdot\frac{9}{14}=\frac{21}{5}=4\frac{1}{5}\).

\(10-4\frac{1}{5}=5\frac{4}{5}\).

Ответ: а) \(-\frac{1}{4}\); б) \(\frac{3}{8}\); в) \(-1\frac{2}{3}\); г) \(5\frac{4}{5}\).