- \(\frac57:\frac34=\frac57\cdot\frac43=\frac{20}{21}\).
- \(\frac5{18}:\frac2{45}=\frac5{18}\cdot\frac{45}{2}=\frac{25}{4}=6\frac14\).
- \(\frac67:3=\frac67\cdot\frac13=\frac27\).
- \(3\frac12:\frac67=\frac72\cdot\frac76=\frac{49}{12}=4\frac1{12}\).
Ответ: 1) 20/21; 2) 6 1/4; 3) 2/7; 4) 4 1/12.