1. Вычислите: 1) \(\frac{21}{40}:\frac{3}{4}\); 2) \(1\frac{5}{9}:1\frac{8}{27}\); 3) \(5\frac{15}{16}:4\); 4) \(\frac{9}{17}:3\).

1) \(\frac{21}{40}:\frac{3}{4} = \frac{21}{40} \cdot \frac{4}{3} = \frac{21 \cdot 4}{40 \cdot 3} = \frac{7 \cdot 1}{10 \cdot 1} = \frac{7}{10}\)

2) \(1\frac{5}{9}:1\frac{8}{27} = \frac{14}{9}:\frac{35}{27} = \frac{14}{9} \cdot \frac{27}{35} = \frac{14 \cdot 27}{9 \cdot 35} = \frac{2 \cdot 3}{1 \cdot 5} = \frac{6}{5} = 1\frac{1}{5}\)

3) \(5\frac{15}{16}:4 = \frac{95}{16}:4 = \frac{95}{16} \cdot \frac{1}{4} = \frac{95}{64} = 1\frac{31}{64}\)

4) \(\frac{9}{17}:3 = \frac{9}{17} \cdot \frac{1}{3} = \frac{9 \cdot 1}{17 \cdot 3} = \frac{3}{17}\)

Ответ: 1) \(\frac{7}{10}\); 2) \(1\frac{1}{5}\); 3) \(1\frac{31}{64}\); 4) \(\frac{3}{17}\)