№3 Решите примеры: a) \(\frac{3}{5} - \frac{1}{10}\) б) \(\frac{3}{10} \times \frac{5}{20}\) в) \(\frac{4}{15} : \frac{2}{10}\) г) \(\frac{5}{21} + \frac{1}{3}\)

Решение:

1. \(\frac{3}{5} - \frac{1}{10} = \frac{6}{10} - \frac{1}{10} = \frac{5}{10} = \frac{1}{2}\)
2. \(\frac{3}{10} \times \frac{5}{20} = \frac{3 \times 5}{10 \times 20} = \frac{15}{200} = \frac{3}{40}\)
3. \(\frac{4}{15} : \frac{2}{10} = \frac{4}{15} \times \frac{10}{2} = \frac{4 \times 10}{15 \times 2} = \frac{40}{30} = \frac{4}{3}\)
4. \(\frac{5}{21} + \frac{1}{3} = \frac{5}{21} + \frac{7}{21} = \frac{12}{21} = \frac{4}{7}\)

Ответ: а) \(\frac{1}{2}\); б) \(\frac{3}{40}\); в) \(\frac{4}{3}\); г) \(\frac{4}{7}\).