4.233 Найдите разность: a) -3/17 - (-9/17); б) -8/17 - (-3/17); в) 7/13 - (-1/13); г) -5/14 - 3/7; д) 1/2 - 4/5; e) -2/3 - (-5/6);

**Решение:** a) $$-\frac{3}{17} - (-\frac{9}{17}) = -\frac{3}{17} + \frac{9}{17} = \frac{-3+9}{17} = \frac{6}{17}$$ б) $$-\frac{8}{17} - (-\frac{3}{17}) = -\frac{8}{17} + \frac{3}{17} = \frac{-8+3}{17} = \frac{-5}{17} = -\frac{5}{17}$$ в) $$\frac{7}{13} - (-\frac{1}{13}) = \frac{7}{13} + \frac{1}{13} = \frac{7+1}{13} = \frac{8}{13}$$ г) $$-\frac{5}{14} - \frac{3}{7} = -\frac{5}{14} - \frac{3 \cdot 2}{7 \cdot 2} = -\frac{5}{14} - \frac{6}{14} = \frac{-5-6}{14} = \frac{-11}{14} = -\frac{11}{14}$$ д) $$\frac{1}{2} - \frac{4}{5} = \frac{1 \cdot 5}{2 \cdot 5} - \frac{4 \cdot 2}{5 \cdot 2} = \frac{5}{10} - \frac{8}{10} = \frac{5-8}{10} = \frac{-3}{10} = -\frac{3}{10}$$ e) $$-\frac{2}{3} - (-\frac{5}{6}) = -\frac{2}{3} + \frac{5}{6} = -\frac{2 \cdot 2}{3 \cdot 2} + \frac{5}{6} = -\frac{4}{6} + \frac{5}{6} = \frac{-4+5}{6} = \frac{1}{6}$$ **Ответ:** a) 6/17 б) -5/17 в) 8/13 г) -11/14 д) -3/10 e) 1/6