1. Вычислите: a) \(\frac{7}{9} - \frac{5}{6} \cdot \frac{4}{15}\); б) \((\frac{2}{3} - \frac{4}{9}) \cdot \frac{3}{8}\); в) \(\frac{2}{7} + \frac{3}{8} : \frac{7}{32}\); г) \(\frac{5}{12} \cdot (\frac{1}{5} + \frac{3}{25})\).

a) \(\frac{7}{9} - \frac{5}{6} \cdot \frac{4}{15}\) = \(\frac{7}{9} - \frac{5 \cdot 4}{6 \cdot 15}\) = \(\frac{7}{9} - \frac{20}{90}\) = \(\frac{7}{9} - \frac{2}{9}\) = \(\frac{7-2}{9}\) = \(\frac{5}{9}\).

б) \((\frac{2}{3} - \frac{4}{9}) \cdot \frac{3}{8}\) = \((\frac{2 \cdot 3}{3 \cdot 3} - \frac{4}{9}) \cdot \frac{3}{8}\) = \((\frac{6}{9} - \frac{4}{9}) \cdot \frac{3}{8}\) = \(\frac{6-4}{9} \cdot \frac{3}{8}\) = \(\frac{2}{9} \cdot \frac{3}{8}\) = \(\frac{2 \cdot 3}{9 \cdot 8}\) = \(\frac{6}{72}\) = \(\frac{1}{12}\).

в) \(\frac{2}{7} + \frac{3}{8} : \frac{7}{32}\) = \(\frac{2}{7} + \frac{3}{8} \cdot \frac{32}{7}\) = \(\frac{2}{7} + \frac{3 \cdot 32}{8 \cdot 7}\) = \(\frac{2}{7} + \frac{96}{56}\) = \(\frac{2}{7} + \frac{12}{7}\) = \(\frac{2+12}{7}\) = \(\frac{14}{7}\) = 2.

г) \(\frac{5}{12} \cdot (\frac{1}{5} + \frac{3}{25})\) = \(\frac{5}{12} \cdot (\frac{1 \cdot 5}{5 \cdot 5} + \frac{3}{25})\) = \(\frac{5}{12} \cdot (\frac{5}{25} + \frac{3}{25})\) = \(\frac{5}{12} \cdot \frac{5+3}{25}\) = \(\frac{5}{12} \cdot \frac{8}{25}\) = \(\frac{5 \cdot 8}{12 \cdot 25}\) = \(\frac{40}{300}\) = \(\frac{2}{15}\).

Ответ: a) \(\frac{5}{9}\); б) \(\frac{1}{12}\); в) 2; г) \(\frac{2}{15}\).