Ответ:

  1. \(\frac49\cdot\frac1{32}=\frac4{288}=\frac1{72}\).
  2. \(\frac59\cdot\frac78=\frac{35}{72}\).
  3. \(\frac{27}{56}\cdot\frac{50}{45}=\frac{3}{7}\cdot\frac{10}{5}=\frac67\).
  4. \(\frac{45}{64}\cdot\frac{40}{69}=\frac5{?}\). Сократим: \(\frac{45}{69}=\frac{15}{23}\), \(\frac{40}{64}=\frac58\), поэтому \(\frac{15}{23}\cdot\frac58=\frac{75}{184}\).

Ответ: 1) \(\frac1{72}\); 2) \(\frac{35}{72}\); 3) \(\frac67\); 4) \(\frac{75}{184}\).