3. Выполните действия: a) 11/17 + 5/17 + 2/17; б) 6 5/8 + 2 7/8; в) 8 - 4 5/7; г) 7 4/15 - 3 11/15

a) \(\frac{11}{17} + \frac{5}{17} + \frac{2}{17} = \frac{11+5+2}{17} = \frac{18}{17} = 1 \frac{1}{17}\) б) \(6 \frac{5}{8} + 2 \frac{7}{8} = (6 + 2) + (\frac{5}{8} + \frac{7}{8}) = 8 + \frac{12}{8} = 8 + 1 \frac{4}{8} = 9 \frac{1}{2}\) в) \(8 - 4 \frac{5}{7} = 7 \frac{7}{7} - 4 \frac{5}{7} = (7 - 4) + (\frac{7}{7} - \frac{5}{7}) = 3 \frac{2}{7}\) г) \(7 \frac{4}{15} - 3 \frac{11}{15} = 6 \frac{19}{15} - 3 \frac{11}{15} = (6 - 3) + (\frac{19}{15} - \frac{11}{15}) = 3 + \frac{8}{15} = 3 \frac{8}{15}\)