Ответ:

а) \(\frac{8}{9}\cdot\frac{3}{4}=\frac{2}{3}\).

б) \(\frac{11}{45}\cdot\frac{9}{22}=\frac{1}{10}\).

в) \(\frac{51}{29}\cdot\frac{58}{85}=\frac{6}{5}\).

г) \(\frac{1}{4}\cdot\frac{4}{5}\cdot\frac{5}{6}=\frac{1}{6}\).

Ответ: а) \(\frac{2}{3}\); б) \(\frac{1}{10}\); в) \(\frac{6}{5}\); г) \(\frac{1}{6}\).