Ответ:

  1. \(\frac{13}{16}\cdot\frac{8}{13}=\frac{1}{2}\).
  2. \(6\cdot\frac{7}{18}=\frac{42}{18}=\frac{7}{3}=2\frac{1}{3}\).
  3. \(\frac{5}{11}\cdot 3\frac{3}{10}=\frac{5}{11}\cdot\frac{33}{10}=\frac{3}{2}=1\frac{1}{2}\).
  4. \(\frac{6}{12}\cdot\frac{4}{21}\cdot\frac{7}{8}=\frac{1}{2}\cdot\frac{4}{21}\cdot\frac{7}{8}=\frac{1}{12}\).
  5. \(2\frac{3}{4}\cdot\frac{12}{13}\cdot 2\frac{4}{11}=\frac{11}{4}\cdot\frac{12}{13}\cdot\frac{26}{11}=6\).

Ответ: 1) \(\frac{1}{2}\); 2) \(2\frac{1}{3}\); 3) \(1\frac{1}{2}\); 4) \(\frac{1}{12}\); 5) \(6\).