1. Выполните умножение: 3 1) — · — ; 7 11 2. Вычислите: 1) 5 · 3/16; 3. Найдите произведение: 1) 3 3/8 · 7/9; 2) 8/15 · 35/48; 2) 18 · 4/9; 2) 4 4/7 · 11/12; 3) 11 5/16 · 3 9/16; 4) 1 2/13 · 1 5/8.

1. Выполните умножение: 1) $$rac{3}{7} \cdot \frac{8}{11} = \frac{3 \cdot 8}{7 \cdot 11} = \frac{24}{77}$$ 2) $$\frac{8}{15} \cdot \frac{35}{48} = \frac{8 \cdot 35}{15 \cdot 48} = \frac{280}{720} = \frac{28}{72} = \frac{7}{18}$$ 2. Вычислите: 1) $$5 \cdot \frac{3}{16} = \frac{5 \cdot 3}{16} = \frac{15}{16}$$ 2) $$18 \div \frac{4}{9} = 18 \cdot \frac{9}{4} = \frac{18 \cdot 9}{4} = \frac{162}{4} = \frac{81}{2} = 40 \frac{1}{2}$$ 3. Найдите произведение: 1) $$3 \frac{3}{8} \cdot \frac{7}{9} = \frac{3 \cdot 8 + 3}{8} \cdot \frac{7}{9} = \frac{27}{8} \cdot \frac{7}{9} = \frac{27 \cdot 7}{8 \cdot 9} = \frac{3 \cdot 7}{8 \cdot 1} = \frac{21}{8} = 2 \frac{5}{8}$$ 2) $$4 \frac{4}{7} \cdot \frac{11}{12} = \frac{4 \cdot 7 + 4}{7} \cdot \frac{11}{12} = \frac{32}{7} \cdot \frac{11}{12} = \frac{32 \cdot 11}{7 \cdot 12} = \frac{8 \cdot 11}{7 \cdot 3} = \frac{88}{21} = 4 \frac{4}{21}$$ 3) $$11 \frac{5}{16} \cdot 3 \frac{9}{16} = \frac{11 \cdot 16 + 5}{16} \cdot \frac{3 \cdot 16 + 9}{16} = \frac{181}{16} \cdot \frac{57}{16} = \frac{181 \cdot 57}{16 \cdot 16} = \frac{10317}{256} = 40 \frac{77}{256}$$ 4) $$1 \frac{2}{13} \cdot 1 \frac{1}{8} = \frac{1 \cdot 13 + 2}{13} \cdot \frac{1 \cdot 8 + 1}{8} = \frac{15}{13} \cdot \frac{9}{8} = \frac{15 \cdot 9}{13 \cdot 8} = \frac{135}{104} = 1 \frac{31}{104}$$