Ответ:

\(\frac{4}{3}:\frac{7}{6}=\frac{4}{3}\cdot\frac{6}{7}=\frac{8}{7}\).

\(\frac{21}{8}-\frac{8}{7}=\frac{147-64}{56}=\frac{83}{56}=1\frac{27}{56}\).

Ответ: \(1\frac{27}{56}\).