4. (5 баллов) 1) $$\frac{3}{8}: \frac{2}{3}$$; 2) $$\frac{5}{16}: \frac{1}{3}$$; 3) $$\frac{7}{8}: \frac{1}{5}$$; 4) $$\frac{5}{6}: \frac{1}{7}$$; 5) $$\frac{1}{9}: \frac{1}{8}$$;

4. (5 баллов)

1) $$\frac{3}{8}: \frac{2}{3} = \frac{3}{8} \cdot \frac{3}{2} = \frac{3 \cdot 3}{8 \cdot 2} = \frac{9}{16}$$

Ответ: $$\frac{9}{16}$$

2) $$\frac{5}{16}: \frac{1}{3} = \frac{5}{16} \cdot \frac{3}{1} = \frac{5 \cdot 3}{16 \cdot 1} = \frac{15}{16}$$

Ответ: $$\frac{15}{16}$$

3) $$\frac{7}{8}: \frac{1}{5} = \frac{7}{8} \cdot \frac{5}{1} = \frac{7 \cdot 5}{8 \cdot 1} = \frac{35}{8} = 4\frac{3}{8}$$

Ответ: $$4\frac{3}{8}$$

4) $$\frac{5}{6}: \frac{1}{7} = \frac{5}{6} \cdot \frac{7}{1} = \frac{5 \cdot 7}{6 \cdot 1} = \frac{35}{6} = 5\frac{5}{6}$$

Ответ: $$5\frac{5}{6}$$

5) $$\frac{1}{9}: \frac{1}{8} = \frac{1}{9} \cdot \frac{8}{1} = \frac{1 \cdot 8}{9 \cdot 1} = \frac{8}{9}$$

Ответ: $$\frac{8}{9}$$