4. Выполните деление: a) 1 : 1/7 = 5 : 5/8 = 4 : 8/9 = 120 : 1/10 = б) 3/7 : 9/14 = 3/10 : 8/11 = 7/12 : 5/6 = 7/8 : 3/4 =

a) \(1 : \frac{1}{7} = 1 \cdot 7 = 7\) \(5 : \frac{5}{8} = 5 \cdot \frac{8}{5} = \frac{5 \cdot 8}{5} = 8\) \(4 : \frac{8}{9} = 4 \cdot \frac{9}{8} = \frac{4 \cdot 9}{8} = \frac{36}{8} = \frac{9}{2} = 4.5\) \(120 : \frac{1}{10} = 120 \cdot 10 = 1200\) б) \(\frac{3}{7} : \frac{9}{14} = \frac{3}{7} \cdot \frac{14}{9} = \frac{3 \cdot 14}{7 \cdot 9} = \frac{2}{3}\) \(\frac{3}{10} : \frac{8}{11} = \frac{3}{10} \cdot \frac{11}{8} = \frac{3 \cdot 11}{10 \cdot 8} = \frac{33}{80}\) \(\frac{7}{12} : \frac{5}{6} = \frac{7}{12} \cdot \frac{6}{5} = \frac{7 \cdot 6}{12 \cdot 5} = \frac{7}{10}\) \(\frac{7}{8} : \frac{3}{4} = \frac{7}{8} \cdot \frac{4}{3} = \frac{7 \cdot 4}{8 \cdot 3} = \frac{7}{6}\)