1) \(\frac{5}{19} + \frac{15}{19} - \frac{13}{19}\); 2) \(6\frac{12}{27} - 4\frac{5}{27} + 6\frac{16}{27}\); 3) \(1 - \frac{9}{17}\); 4) \(9\frac{3}{12} - 5\frac{8}{12}\).

1) \(\frac{5}{19} + \frac{15}{19} - \frac{13}{19} = \frac{5 + 15 - 13}{19} = \frac{7}{19}\). 2) \(6\frac{12}{27} - 4\frac{5}{27} + 6\frac{16}{27} = (6 - 4 + 6) + (\frac{12}{27} - \frac{5}{27} + \frac{16}{27}) = 8 + \frac{12 - 5 + 16}{27} = 8 + \frac{23}{27} = 8\frac{23}{27}\). 3) \(1 - \frac{9}{17} = \frac{17}{17} - \frac{9}{17} = \frac{17 - 9}{17} = \frac{8}{17}\). 4) \(9\frac{3}{12} - 5\frac{8}{12}\). Так как дробь \(\frac{3}{12}\) меньше \(\frac{8}{12}\), нужно занять единицу у 9: \(9\frac{3}{12} = 8\frac{12+3}{12} = 8\frac{15}{12}\). Тогда \(8\frac{15}{12} - 5\frac{8}{12} = (8 - 5) + (\frac{15}{12} - \frac{8}{12}) = 3 + \frac{15 - 8}{12} = 3 + \frac{7}{12} = 3\frac{7}{12}\).