№1. Выполни умножение дробей: 1) $$\frac{1}{2} \cdot \frac{1}{3}$$ 2) $$\frac{2}{5} \cdot \frac{3}{4}$$ 3) $$\frac{5}{7} \cdot 2$$ 4) $$\frac{7}{10} \cdot \frac{3}{4}$$ 5) $$\frac{1}{4} \cdot \frac{2}{3}$$ 6) $$\frac{2}{3} \cdot \frac{3}{8}$$ 7) $$\frac{15}{16} \cdot \frac{8}{25}$$ 8) $$\frac{3}{4} \cdot \frac{1}{6}$$

Решение:

1. $$\frac{1}{2} \cdot \frac{1}{3} = \frac{1 \cdot 1}{2 \cdot 3} = \frac{1}{6}$$
2. $$\frac{2}{5} \cdot \frac{3}{4} = \frac{2 \cdot 3}{5 \cdot 4} = \frac{6}{20} = \frac{3}{10}$$
3. $$\frac{5}{7} \cdot 2 = \frac{5}{7} \cdot \frac{2}{1} = \frac{5 \cdot 2}{7 \cdot 1} = \frac{10}{7} = 1\frac{3}{7}$$
4. $$\frac{7}{10} \cdot \frac{3}{4} = \frac{7 \cdot 3}{10 \cdot 4} = \frac{21}{40}$$
5. $$\frac{1}{4} \cdot \frac{2}{3} = \frac{1 \cdot 2}{4 \cdot 3} = \frac{2}{12} = \frac{1}{6}$$
6. $$\frac{2}{3} \cdot \frac{3}{8} = \frac{2 \cdot 3}{3 \cdot 8} = \frac{6}{24} = \frac{1}{4}$$
7. $$\frac{15}{16} \cdot \frac{8}{25} = \frac{15 \cdot 8}{16 \cdot 25} = \frac{3 \cdot 5 \cdot 8}{2 \cdot 8 \cdot 5 \cdot 5} = \frac{3}{2 \cdot 5} = \frac{3}{10}$$
8. $$\frac{3}{4} \cdot \frac{1}{6} = \frac{3 \cdot 1}{4 \cdot 6} = \frac{3}{24} = \frac{1}{8}$$

Ответ: 1) $$\frac{1}{6}$$; 2) $$\frac{3}{10}$$; 3) $$1\frac{3}{7}$$; 4) $$\frac{21}{40}$$; 5) $$\frac{1}{6}$$; 6) $$\frac{1}{4}$$; 7) $$\frac{3}{10}$$; 8) $$\frac{1}{8}$$.