Ответ:

а) \(\frac{10}{27}\cdot\frac{9}{25}=\frac{2}{15}\).

б) \(\frac{11}{14}\cdot\frac{28}{33}\cdot\frac{6}{5}=\frac{4}{5}\).

в) \(12\cdot\frac{7}{36}=\frac{7}{3}=2\frac{1}{3}\).

г) \(2\frac{1}{2}\cdot\frac{4}{15}=\frac{5}{2}\cdot\frac{4}{15}=\frac{2}{3}\).