a) \(\frac{14}{21} = \frac{2}{3}\)
\(\frac{12}{30} = \frac{2}{5}\)
\(\frac{24}{60} = \frac{2}{5}\)
\(\frac{35}{105} = \frac{1}{3}\)
Ответ: \(\frac{2}{3}\), \(\frac{2}{5}\), \(\frac{2}{5}\), \(\frac{1}{3}\)