Ответ:

\(\frac{3}{4}+\frac{1}{12}=\frac{9}{12}+\frac{1}{12}=\frac{5}{6}\).

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

Ответ: \(\frac{9}{20}\).