2) Вычислите, используя свойство вычитания суммы из числа: a) \(\frac{13}{14} - (\frac{3}{14} + \frac{1}{2})\); б) \(\frac{13}{21} - (\frac{1}{3} + \frac{4}{21})\).

а) \(\frac{13}{14} - (\frac{3}{14} + \frac{1}{2})\)

1. \(\frac{1}{2} = \frac{1 \cdot 7}{2 \cdot 7} = \frac{7}{14}\)
2. \(\frac{3}{14} + \frac{7}{14} = \frac{3+7}{14} = \frac{10}{14}\)
3. \(\frac{13}{14} - \frac{10}{14} = \frac{13-10}{14} = \frac{3}{14}\)

Ответ: \(\frac{3}{14}\)

б) \(\frac{13}{21} - (\frac{1}{3} + \frac{4}{21})\)

1. \(\frac{1}{3} = \frac{1 \cdot 7}{3 \cdot 7} = \frac{7}{21}\)
2. \(\frac{7}{21} + \frac{4}{21} = \frac{7+4}{21} = \frac{11}{21}\)
3. \(\frac{13}{21} - \frac{11}{21} = \frac{13-11}{21} = \frac{2}{21}\)

Ответ: \(\frac{2}{21}\)