Ответ:

  1. а) \(3\frac35 : 1\frac{11}{25}=\frac{18}{5}:\frac{36}{25}=\frac{18}{5}\cdot\frac{25}{36}=\frac52=2\frac12\).
  2. б) \(11\frac13:2\frac4{21}:4\frac14=\frac{34}{3}:\frac{46}{21}:\frac{17}{4}=\frac{34}{3}\cdot\frac{21}{46}\cdot\frac4{17}=4\).
  3. в) \(7\frac18:4\frac34\cdot8=\frac{57}{8}:\frac{19}{4}\cdot8=\frac32\cdot8=12\).
  4. г) \(\frac78\cdot\frac89:1\frac19=\frac79:\frac{10}{9}=\frac7{10}\).
  5. д) \(1\frac79\cdot2\frac25:1\frac35=\frac{16}{9}\cdot\frac{12}{5}:\frac85=\frac83\).

Ответ: а) 2 1/2; б) 4; в) 12; г) 7/10; д) 2 2/3.