Решение:

1. А) $$\frac{3}{8} \cdot \frac{7}{11} = \frac{3 \cdot 7}{8 \cdot 11} = \frac{21}{88}$$
2. Б) $$\frac{8}{9} \cdot \frac{27}{32} = \frac{8 \cdot 27}{9 \cdot 32} = \frac{8 \cdot 3 \cdot 9}{9 \cdot 4 \cdot 8} = \frac{3}{4}$$
3. В) $$1\frac{3}{5} \cdot 1\frac{7}{8} = \frac{1 \cdot 5 + 3}{5} \cdot \frac{1 \cdot 8 + 7}{8} = \frac{8}{5} \cdot \frac{15}{8} = \frac{8 \cdot 15}{5 \cdot 8} = \frac{15}{5} = 3$$
4. Г) $$2\frac{3}{4} \cdot 1\frac{1}{22} = \frac{2 \cdot 4 + 3}{4} \cdot \frac{1 \cdot 22 + 1}{22} = \frac{11}{4} \cdot \frac{23}{22} = \frac{11 \cdot 23}{4 \cdot 22} = \frac{23}{8} = 2\frac{7}{8}$$
5. Д) $$3\frac{3}{5} \cdot 5 = \frac{3 \cdot 5 + 3}{5} \cdot 5 = \frac{18}{5} \cdot 5 = 18$$