Выполним умножение дробей:
a) $$\frac{3}{8} \cdot \frac{9}{11} = \frac{3 \cdot 9}{8 \cdot 11} = \frac{27}{88}$$
б) $$\frac{3}{5} \cdot \frac{4}{21} = \frac{3 \cdot 4}{5 \cdot 21} = \frac{12}{105} = \frac{4}{35}$$
в) $$1 \frac{5}{15} \cdot \frac{5}{16} = \frac{20}{15} \cdot \frac{5}{16} = \frac{20 \cdot 5}{15 \cdot 16} = \frac{100}{240} = \frac{5}{12}$$
б) $$\frac{22}{35} \cdot \frac{21}{44} = \frac{22 \cdot 21}{35 \cdot 44} = \frac{462}{1540} = \frac{3}{10}$$
г) $$9 \frac{1}{7} \cdot \frac{3}{11} = \frac{64}{7} \cdot \frac{3}{11} = \frac{64 \cdot 3}{7 \cdot 11} = \frac{192}{77} = 2 \frac{38}{77}$$
e) $$\frac{7}{11} \cdot \frac{2}{14} = \frac{7 \cdot 2}{11 \cdot 14} = \frac{14}{154} = \frac{1}{11}$$
Ответ: a) 27/88; б) 4/35; в) 5/12; б) 3/10; г) 2 38/77; e) 1/11