Ответ:

  1. \(5\cdot\frac{3}{16}=\frac{15}{16}\).
  2. \(18\cdot\frac{4}{9}=2\cdot4=8\).
  3. \(\frac{13}{27}\cdot3=\frac{13}{9}\).
  4. \(\frac{11}{40}\cdot16=\frac{11}{5}\cdot2=\frac{22}{5}=4\frac{2}{5}\).

Ответ: 1) \(\frac{15}{16}\); 2) 8; 3) \(\frac{13}{9}\); 4) \(\frac{22}{5}\).