Вычислите: 7/9 * 5/6 * 4/15

1. $\frac{7}{9} \cdot \frac{5}{6} \cdot \frac{4}{15} = \frac{7 \cdot 5 \cdot 4}{9 \cdot 6 \cdot 15} = \frac{7 \cdot 1 \cdot 2}{9 \cdot 3 \cdot 3} = \frac{14}{81}$ **Ответ: 14/81** 2. $(\frac{2}{3} - \frac{4}{9}) \cdot \frac{3}{8} = (\frac{6}{9} - \frac{4}{9}) \cdot \frac{3}{8} = \frac{2}{9} \cdot \frac{3}{8} = \frac{1 \cdot 1}{3 \cdot 4} = \frac{1}{12}$ **Ответ: 1/12** 3. $\frac{2}{7} \cdot \frac{3}{8} \cdot \frac{7}{32} = \frac{2 \cdot 3 \cdot 7}{7 \cdot 8 \cdot 32} = \frac{1 \cdot 3 \cdot 1}{1 \cdot 4 \cdot 32} = \frac{3}{128}$ **Ответ: 3/128** 4. $\frac{5}{9} : (\frac{7}{9} + \frac{11}{18}) = \frac{5}{9} : (\frac{14}{18} + \frac{11}{18}) = \frac{5}{9} : \frac{25}{18} = \frac{5}{9} \cdot \frac{18}{25} = \frac{1 \cdot 2}{1 \cdot 5} = \frac{2}{5}$ **Ответ: 2/5** 5. $1 - \frac{4}{7} : \frac{16}{21} = 1 - \frac{4}{7} \cdot \frac{21}{16} = 1 - \frac{1 \cdot 3}{1 \cdot 4} = 1 - \frac{3}{4} = \frac{1}{4}$ **Ответ: 1/4** 6. $\frac{5}{12} : (\frac{1}{5} + \frac{3}{25}) = \frac{5}{12} : (\frac{5}{25} + \frac{3}{25}) = \frac{5}{12} : \frac{8}{25} = \frac{5}{12} \cdot \frac{25}{8} = \frac{125}{96} = 1\frac{29}{96}$ **Ответ: 125/96** 7. $\frac{7}{39} : (\frac{1}{7} + \frac{6}{49}) = \frac{7}{39} : (\frac{7}{49} + \frac{6}{49}) = \frac{7}{39} : \frac{13}{49} = \frac{7}{39} \cdot \frac{49}{13} = \frac{343}{507}$ **Ответ: 343/507** 8. $\frac{9}{14} \cdot (\frac{17}{24} - \frac{5}{12}) = \frac{9}{14} \cdot (\frac{17}{24} - \frac{10}{24}) = \frac{9}{14} \cdot \frac{7}{24} = \frac{3 \cdot 1}{2 \cdot 8} = \frac{3}{16}$ **Ответ: 3/16** 9. $\frac{3}{16} : (\frac{4}{5} - \frac{8}{15}) = \frac{3}{16} : (\frac{12}{15} - \frac{8}{15}) = \frac{3}{16} : \frac{4}{15} = \frac{3}{16} \cdot \frac{15}{4} = \frac{45}{64}$ **Ответ: 45/64** 10. $\frac{8}{35} : (\frac{5}{6} - \frac{11}{12}) = \frac{8}{35} : (\frac{10}{12} - \frac{11}{12}) = \frac{8}{35} : (-\frac{1}{12}) = -\frac{8}{35} \cdot 12 = -\frac{96}{35} = -2\frac{26}{35}$ **Ответ: -96/35**