5.357 Сократите дроби: a) \( \frac{6}{10}, \frac{6}{18}, \frac{9}{15}, \frac{9}{21} \) b) \( \frac{2}{12}, \frac{3}{15}, \frac{30}{6}, \frac{7}{42} \) c) \( \frac{12}{60}, \frac{99}{22}, \frac{5}{100}, \frac{20}{1000} \)

a) \( \frac{6}{10} = \frac{3}{5}, \frac{6}{18} = \frac{1}{3}, \frac{9}{15} = \frac{3}{5}, \frac{9}{21} = \frac{3}{7} \) b) \( \frac{2}{12} = \frac{1}{6}, \frac{3}{15} = \frac{1}{5}, \frac{30}{6} = 5, \frac{7}{42} = \frac{1}{6} \) c) \( \frac{12}{60} = \frac{1}{5}, \frac{99}{22} = \frac{9}{2}, \frac{5}{100} = \frac{1}{20}, \frac{20}{1000} = \frac{1}{50} \)