4/5 : 1/2 =

Для деления обыкновенных дробей нужно делимое умножить на дробь, обратную делителю: $\frac{a}{b} : \frac{c}{d} = \frac{a}{b} \cdot \frac{d}{c} = \frac{a \cdot d}{b \cdot c}$. 1. $\frac{4}{5} : \frac{1}{2} = \frac{4}{5} \cdot \frac{2}{1} = \frac{8}{5} = 1\frac{3}{5}$ 2. $\frac{3}{7} : \frac{6}{7} = \frac{3}{7} \cdot \frac{7}{6} = \frac{3 \cdot 7}{7 \cdot 6} = \frac{1}{2}$ 3. $\frac{1}{2} : \frac{3}{4} = \frac{1}{2} \cdot \frac{4}{3} = \frac{4}{6} = \frac{2}{3}$ 4. $\frac{5}{7} : \frac{5}{7} = \frac{5}{7} \cdot \frac{7}{5} = 1$ 5. $\frac{8}{11} : \frac{16}{77} = \frac{8}{11} \cdot \frac{77}{16} = \frac{1 \cdot 7}{1 \cdot 2} = \frac{7}{2} = 3\frac{1}{2}$ 6. $\frac{5}{23} : \frac{15}{46} = \frac{5}{23} \cdot \frac{46}{15} = \frac{1 \cdot 2}{1 \cdot 3} = \frac{2}{3}$ 7. $\frac{14}{25} : \frac{21}{50} = \frac{14}{25} \cdot \frac{50}{21} = \frac{2 \cdot 2}{1 \cdot 3} = \frac{4}{3} = 1\frac{1}{3}$ 8. $\frac{18}{20} : \frac{27}{40} = \frac{18}{20} \cdot \frac{40}{27} = \frac{2 \cdot 2}{1 \cdot 3} = \frac{4}{3} = 1\frac{1}{3}$ 9. $\frac{63}{70} : \frac{81}{270} = \frac{63}{70} \cdot \frac{270}{81} = \frac{9}{10} \cdot \frac{10}{3} = 3$ 10. $\frac{2}{33} : \frac{24}{30} = \frac{2}{33} \cdot \frac{30}{24} = \frac{2}{33} \cdot \frac{5}{4} = \frac{1}{33} \cdot \frac{5}{2} = \frac{5}{66}$