209 Выполните сложение: a) 4/13 + (-4/13); б) 2 1/4 + (-1 1/6); в) -1 + 3/8; г) -4/7 + 2/3; д) -1 5/12 + 7/9; e) 8/15 + (-7/10).

a) \(\frac{4}{13} + (-\frac{4}{13}) = \frac{4}{13} - \frac{4}{13} = 0\) б) \(2 \frac{1}{4} + (-1 \frac{1}{6}) = 2 \frac{1}{4} - 1 \frac{1}{6} = \frac{9}{4} - \frac{7}{6} = \frac{27}{12} - \frac{14}{12} = \frac{13}{12} = 1 \frac{1}{12}\) в) \(-1 + \frac{3}{8} = -\frac{8}{8} + \frac{3}{8} = \frac{-8 + 3}{8} = \frac{-5}{8} = -\frac{5}{8}\) г) \(-\frac{4}{7} + \frac{2}{3} = -\frac{12}{21} + \frac{14}{21} = \frac{-12 + 14}{21} = \frac{2}{21}\) д) \(-1 \frac{5}{12} + \frac{7}{9} = -\frac{17}{12} + \frac{7}{9} = -\frac{51}{36} + \frac{28}{36} = \frac{-51 + 28}{36} = \frac{-23}{36} = -\frac{23}{36}\) e) \(\frac{8}{15} + (-\frac{7}{10}) = \frac{8}{15} - \frac{7}{10} = \frac{16}{30} - \frac{21}{30} = \frac{16 - 21}{30} = \frac{-5}{30} = -\frac{1}{6}\)