Вычисли дроби в заданиях 1-6

Привет! Давай решим эти примеры вместе. 1. $\frac{7}{9} - \frac{5}{6} + \frac{4}{15} = \frac{7 \cdot 10}{9 \cdot 10} - \frac{5 \cdot 15}{6 \cdot 15} + \frac{4 \cdot 6}{15 \cdot 6} = \frac{70}{90} - \frac{75}{90} + \frac{24}{90} = \frac{70 - 75 + 24}{90} = \frac{19}{90}$ 2. $\left( \frac{2}{3} - \frac{4}{9} \right) \cdot \frac{3}{8} = \left( \frac{2 \cdot 3}{3 \cdot 3} - \frac{4}{9} \right) \cdot \frac{3}{8} = \left( \frac{6}{9} - \frac{4}{9} \right) \cdot \frac{3}{8} = \frac{2}{9} \cdot \frac{3}{8} = \frac{2 \cdot 3}{9 \cdot 8} = \frac{6}{72} = \frac{1}{12}$ 3. $\frac{2}{7} + \frac{3}{8} : \frac{7}{32} = \frac{2}{7} + \frac{3}{8} \cdot \frac{32}{7} = \frac{2}{7} + \frac{3 \cdot 32}{8 \cdot 7} = \frac{2}{7} + \frac{96}{56} = \frac{2}{7} + \frac{12}{7} = \frac{2 + 12}{7} = \frac{14}{7} = 2$ 4. $\frac{5}{9} : \left( \frac{7}{9} + \frac{11}{18} \right) = \frac{5}{9} : \left( \frac{7 \cdot 2}{9 \cdot 2} + \frac{11}{18} \right) = \frac{5}{9} : \left( \frac{14}{18} + \frac{11}{18} \right) = \frac{5}{9} : \frac{25}{18} = \frac{5}{9} \cdot \frac{18}{25} = \frac{5 \cdot 18}{9 \cdot 25} = \frac{90}{225} = \frac{2}{5}$ 5. $1 - \frac{4}{7} : \frac{16}{21} = 1 - \frac{4}{7} \cdot \frac{21}{16} = 1 - \frac{4 \cdot 21}{7 \cdot 16} = 1 - \frac{84}{112} = 1 - \frac{3}{4} = \frac{4}{4} - \frac{3}{4} = \frac{1}{4}$ 6. $\frac{5}{12} : \left( \frac{1}{5} + \frac{3}{25} \right) = \frac{5}{12} : \left( \frac{1 \cdot 5}{5 \cdot 5} + \frac{3}{25} \right) = \frac{5}{12} : \left( \frac{5}{25} + \frac{3}{25} \right) = \frac{5}{12} : \frac{8}{25} = \frac{5}{12} \cdot \frac{25}{8} = \frac{5 \cdot 25}{12 \cdot 8} = \frac{125}{96}$ **Ответы:** 1. $\frac{19}{90}$ 2. $\frac{1}{12}$ 3. $2$ 4. $\frac{2}{5}$ 5. $\frac{1}{4}$ 6. $\frac{125}{96}$