1) Вычислите: ($$\frac{3}{5}-\frac{9}{20}$$)$$\cdot$$\frac{5}{6}$$
- $$\frac{3}{5}-\frac{9}{20}=\frac{3\cdot4}{5\cdot4}-\frac{9}{20}=\frac{12}{20}-\frac{9}{20}=\frac{3}{20}$$
- $$\frac{3}{20}\cdot\frac{5}{6}=\frac{3\cdot5}{20\cdot6}=\frac{15}{120}=\frac{1}{8}$$
Ответ: $$\frac{1}{8}$$