Вычислите: 7/9 - 5/6 * 4/15

1. $\frac{7}{9} - \frac{5}{6} \cdot \frac{4}{15} = \frac{7}{9} - \frac{1 \cdot 2}{3 \cdot 3} = \frac{7}{9} - \frac{2}{9} = \frac{5}{9}$ 2. $(\frac{2}{3} - \frac{4}{9}) \cdot \frac{3}{8} = (\frac{6}{9} - \frac{4}{9}) \cdot \frac{3}{8} = \frac{2}{9} \cdot \frac{3}{8} = \frac{1 \cdot 1}{3 \cdot 4} = \frac{1}{12}$ 3. $\frac{2}{7} + \frac{3}{8} : \frac{7}{32} = \frac{2}{7} + \frac{3}{8} \cdot \frac{32}{7} = \frac{2}{7} + \frac{3 \cdot 4}{7} = \frac{2}{7} + \frac{12}{7} = \frac{14}{7} = 2$ 4. $\frac{5}{9} : (\frac{7}{9} + \frac{11}{18}) = \frac{5}{9} : (\frac{14}{18} + \frac{11}{18}) = \frac{5}{9} : \frac{25}{18} = \frac{5}{9} \cdot \frac{18}{25} = \frac{1 \cdot 2}{1 \cdot 5} = \frac{2}{5}$ 5. $1 - \frac{4}{7} \cdot \frac{16}{21} = 1 - \frac{64}{147} = \frac{147 - 64}{147} = \frac{83}{147}$ 6. $\frac{5}{12} \cdot (\frac{1}{5} + \frac{3}{25}) = \frac{5}{12} \cdot (\frac{5}{25} + \frac{3}{25}) = \frac{5}{12} \cdot \frac{8}{25} = \frac{1 \cdot 2}{3 \cdot 5} = \frac{2}{15}$ 7. $\frac{7}{39} \cdot (\frac{1}{7} + \frac{6}{49}) = \frac{7}{39} \cdot (\frac{7}{49} + \frac{6}{49}) = \frac{7}{39} \cdot \frac{13}{49} = \frac{1 \cdot 1}{3 \cdot 7} = \frac{1}{21}$ 8. $\frac{9}{14} \cdot (\frac{17}{24} - \frac{5}{12}) = \frac{9}{14} \cdot (\frac{17}{24} - \frac{10}{24}) = \frac{9}{14} \cdot \frac{7}{24} = \frac{3 \cdot 1}{2 \cdot 8} = \frac{3}{16}$ 9. $\frac{3}{16} \cdot (\frac{4}{5} + \frac{8}{15}) = \frac{3}{16} \cdot (\frac{12}{15} + \frac{8}{15}) = \frac{3}{16} \cdot \frac{20}{15} = \frac{3}{16} \cdot \frac{4}{3} = \frac{1 \cdot 1}{4 \cdot 1} = \frac{1}{4}$ 10. $\frac{8}{35} \cdot (\frac{5}{6} + \frac{11}{12}) = \frac{8}{35} \cdot (\frac{10}{12} + \frac{11}{12}) = \frac{8}{35} \cdot \frac{21}{12} = \frac{2 \cdot 3}{5 \cdot 3} = \frac{2}{5}$ 11. $\frac{8}{15} \cdot (\frac{7}{8} + \frac{11}{16}) = \frac{8}{15} \cdot (\frac{14}{16} + \frac{11}{16}) = \frac{8}{15} \cdot \frac{25}{16} = \frac{1 \cdot 5}{3 \cdot 2} = \frac{5}{6}$