4. Выполните деление: а) 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. в) 12 : 5/8; 1/3 : 3; 5/7 : 10; 10/11 : 5. г) 1/200 : 200; 9/16 : 6; 84/121 : 63/110.

При делении на дробь умножаем на обратную дробь.

а)

1. \(1 : \frac{1}{7}=1\cdot 7=7\).
2. \(5 : \frac{5}{8}=5\cdot\frac{8}{5}=8\).
3. \(4 : \frac{8}{9}=4\cdot\frac{9}{8}=\frac{9}{2}=4\frac{1}{2}\).
4. \(120 : \frac{1}{10}=120\cdot 10=1200\).

б)

1. \(\frac{3}{7}:\frac{9}{14}=\frac{3}{7}\cdot\frac{14}{9}=\frac{2}{3}\).
2. \(\frac{3}{10}:\frac{8}{11}=\frac{3}{10}\cdot\frac{11}{8}=\frac{33}{80}\).
3. \(\frac{7}{12}:\frac{5}{6}=\frac{7}{12}\cdot\frac{6}{5}=\frac{7}{10}\).
4. \(\frac{7}{8}:\frac{3}{4}=\frac{7}{8}\cdot\frac{4}{3}=\frac{7}{6}=1\frac{1}{6}\).

в)

1. \(12:\frac{5}{8}=12\cdot\frac{8}{5}=\frac{96}{5}=19\frac{1}{5}\).
2. \(\frac{1}{3}:3=\frac{1}{3}\cdot\frac{1}{3}=\frac{1}{9}\).
3. \(\frac{5}{7}:10=\frac{5}{7}\cdot\frac{1}{10}=\frac{1}{14}\).
4. \(\frac{10}{11}:5=\frac{10}{11}\cdot\frac{1}{5}=\frac{2}{11}\).

г)

1. \(\frac{1}{200}:200=\frac{1}{200}\cdot\frac{1}{200}=\frac{1}{40000}\).
2. \(\frac{9}{16}:6=\frac{9}{16}\cdot\frac{1}{6}=\frac{3}{32}\).
3. \(\frac{84}{121}:\frac{63}{110}=\frac{84}{121}\cdot\frac{110}{63}=\frac{40}{33}=1\frac{7}{33}\).

Ответ: а) 7; 8; 4 1/2; 1200. б) 2/3; 33/80; 7/10; 1 1/6. в) 19 1/5; 1/9; 1/14; 2/11. г) 1/40000; 3/32; 1 7/33.