а) \(\frac{2}{3}\cdot\frac{3}{8}=\frac{1}{4}\).
б) \(\frac{7}{9}\cdot1\frac{1}{8}=\frac{7}{9}\cdot\frac{9}{8}=\frac{7}{8}\).
в) \(\frac{5}{16}:3\frac{1}{8}=\frac{5}{16}:\frac{25}{8}=\frac{5}{16}\cdot\frac{8}{25}=\frac{1}{10}\).
Ответ: а) \(\frac{1}{4}\); б) \(\frac{7}{8}\); в) \(\frac{1}{10}\).