Ответ:

  1. Сократим 5 с 16: \(5\cdot\frac{3}{16}=\frac{15}{16}\).

  2. Сократим 18 с 9: \(18\cdot\frac{4}{9}=2\cdot4=8\).

  3. \(\frac{13}{27}\cdot3=\frac{13}{9}=1\frac{4}{9}\).

  4. \(\frac{11}{40}\cdot16=\frac{11}{5}\cdot2=\frac{22}{5}=4\frac{2}{5}\).

Ответ: 1) 15/16; 2) 8; 3) 1 4/9; 4) 4 2/5.