Задание 11: Сложение и вычитание дробей

Задание 11. Вычислите: а) \(\frac{1}{3} + \frac{5}{6} = \frac{1 \cdot 2}{6} + \frac{5}{6} = \frac{2 + 5}{6} = \frac{7}{6} = 1\frac{1}{6}\) б) \(\frac{5}{6} - \frac{1}{2} = \frac{5}{6} - \frac{1 \cdot 3}{6} = \frac{5 - 3}{6} = \frac{2}{6} = \frac{1}{3}\) в) \(\frac{9}{10} - \frac{4}{5} = \frac{9}{10} - \frac{4 \cdot 2}{10} = \frac{9 - 8}{10} = \frac{1}{10}\) г) \(\frac{5}{6} - \frac{5}{12} = \frac{5 \cdot 2}{12} - \frac{5}{12} = \frac{10 - 5}{12} = \frac{5}{12}\) д) \(\frac{11}{18} + \frac{1}{6} = \frac{11}{18} + \frac{1 \cdot 3}{18} = \frac{11 + 3}{18} = \frac{14}{18} = \frac{7}{9}\) е) \(\frac{5}{12} + \frac{3}{4} = \frac{5}{12} + \frac{3 \cdot 3}{12} = \frac{5 + 9}{12} = \frac{14}{12} = \frac{7}{6} = 1\frac{1}{6}\) ж) \(\frac{4}{5} - \frac{7}{15} = \frac{4 \cdot 3}{15} - \frac{7}{15} = \frac{12 - 7}{15} = \frac{5}{15} = \frac{1}{3}\) з) \(\frac{11}{21} + \frac{3}{7} = \frac{11}{21} + \frac{3 \cdot 3}{21} = \frac{11 + 9}{21} = \frac{20}{21}\)