17. Сократите дробь: 1) 5/15; 2) 12/18; 3) 27/45; 4) 30/48.

1. \(\frac{5}{15}=\frac{5:5}{15:5}=\frac{1}{3}\).
2. \(\frac{12}{18}=\frac{12:6}{18:6}=\frac{2}{3}\).
3. \(\frac{27}{45}=\frac{27:9}{45:9}=\frac{3}{5}\).
4. \(\frac{30}{48}=\frac{30:6}{48:6}=\frac{5}{8}\).

Ответ: 1) \(\frac{1}{3}\); 2) \(\frac{2}{3}\); 3) \(\frac{3}{5}\); 4) \(\frac{5}{8}\).