13. Вычислите: \(\frac{3}{24}:\frac{3}{64}-\frac{3}{4}\).

\[\frac{3}{24}:\frac{3}{64}=\frac{3}{24}\cdot\frac{64}{3}=\frac{8}{3}.\]

\[\frac{8}{3}-\frac{3}{4}=\frac{32}{12}-\frac{9}{12}=\frac{23}{12}=1\frac{11}{12}.\]

Ответ: \(1\frac{11}{12}\).