Решение примеров на умножение и деление обыкновенных дробей

1) $$\frac{5}{6} \cdot \frac{3}{20} = \frac{5 \cdot 3}{6 \cdot 20} = \frac{15}{120} = \frac{1}{8}$$

2) $$\frac{3}{7} \cdot \frac{6}{11} = \frac{3 \cdot 6}{7 \cdot 11} = \frac{18}{77}$$

3) $$\frac{10}{11} \cdot \frac{11}{26} = \frac{10 \cdot 11}{11 \cdot 26} = \frac{110}{286} = \frac{5}{13}$$

4) $$\frac{19}{42} \cdot \frac{21}{38} = \frac{19 \cdot 21}{42 \cdot 38} = \frac{399}{1596} = \frac{1}{4}$$

5) $$\frac{3}{4} : \frac{33}{20} = \frac{3}{4} \cdot \frac{20}{33} = \frac{3 \cdot 20}{4 \cdot 33} = \frac{60}{132} = \frac{5}{11}$$

6) $$\frac{25}{72} : \frac{45}{63} = \frac{25}{72} \cdot \frac{63}{45} = \frac{25 \cdot 63}{72 \cdot 45} = \frac{1575}{3240} = \frac{35}{72}$$

7) $$\frac{8}{15} : 24 = \frac{8}{15} \cdot \frac{1}{24} = \frac{8 \cdot 1}{15 \cdot 24} = \frac{8}{360} = \frac{1}{45}$$

8) $$8 : \frac{4}{5} = 8 \cdot \frac{5}{4} = \frac{8 \cdot 5}{4} = \frac{40}{4} = 10$$

9) $$\frac{2}{3} : \frac{6}{7} : \frac{4}{7} = \frac{2}{3} \cdot \frac{7}{6} \cdot \frac{7}{4} = \frac{2 \cdot 7 \cdot 7}{3 \cdot 6 \cdot 4} = \frac{98}{72} = \frac{49}{36} = 1 \frac{13}{36}$$

10) $$\frac{11}{12} : \frac{7}{24} : \frac{21}{22} = \frac{11}{12} \cdot \frac{24}{7} \cdot \frac{22}{21} = \frac{11 \cdot 24 \cdot 22}{12 \cdot 7 \cdot 21} = \frac{5808}{1764} = \frac{44}{1}$$