678. Найдите значение выражения: 1) $$2\frac{1}{3}:2\frac{2}{3} \cdot 1\frac{3}{5}$$; 3) $$1\frac{1}{9} \cdot 2\frac{1}{5} : 7\frac{1}{3}$$; 2) $$2\frac{1}{4} \cdot \frac{12}{13} : 3\frac{3}{8}$$; 4) $$3\frac{2}{3} : 7\frac{1}{3} \cdot \frac{2}{5}$$

1. $$2\frac{1}{3}:2\frac{2}{3} \cdot 1\frac{3}{5} = \frac{7}{3}:\frac{8}{3} \cdot \frac{8}{5} = \frac{7}{3} \cdot \frac{3}{8} \cdot \frac{8}{5} = \frac{7 \cdot 3 \cdot 8}{3 \cdot 8 \cdot 5} = \frac{7}{5} = 1\frac{2}{5}$$
2. $$2\frac{1}{4} \cdot \frac{12}{13} : 3\frac{3}{8} = \frac{9}{4} \cdot \frac{12}{13} : \frac{27}{8} = \frac{9}{4} \cdot \frac{12}{13} \cdot \frac{8}{27} = \frac{9 \cdot 12 \cdot 8}{4 \cdot 13 \cdot 27} = \frac{1 \cdot 3 \cdot 2}{1 \cdot 13 \cdot 3} = \frac{6}{13}$$
3. $$1\frac{1}{9} \cdot 2\frac{1}{5} : 7\frac{1}{3} = \frac{10}{9} \cdot \frac{11}{5} : \frac{22}{3} = \frac{10}{9} \cdot \frac{11}{5} \cdot \frac{3}{22} = \frac{10 \cdot 11 \cdot 3}{9 \cdot 5 \cdot 22} = \frac{2 \cdot 1 \cdot 1}{3 \cdot 1 \cdot 2} = \frac{2}{6} = \frac{1}{3}$$
4. $$3\frac{2}{3} : 7\frac{1}{3} \cdot \frac{2}{5} = \frac{11}{3} : \frac{22}{3} \cdot \frac{2}{5} = \frac{11}{3} \cdot \frac{3}{22} \cdot \frac{2}{5} = \frac{11 \cdot 3 \cdot 2}{3 \cdot 22 \cdot 5} = \frac{1 \cdot 1 \cdot 1}{1 \cdot 1 \cdot 5} = \frac{1}{5}$$

Ответ: 1) $$1\frac{2}{5}$$; 2) $$\frac{6}{13}$$; 3) $$\frac{1}{3}$$; 4) $$\frac{1}{5}$$