1. Вычислите: а) 19+16 17 28 28 28 =¿ б)55-33+711=¿ 42 42 42 42 в) 248+3=¿ г) 1-=8 2 18 17

а) \(\frac{19}{28} + \frac{16}{28} - \frac{17}{28} = \frac{19+16-17}{28} = \frac{18}{28} = \frac{9}{14}\)

б) \(5\frac{5}{42} - 3\frac{3}{42} + 7\frac{11}{42} = (5-3+7) + (\frac{5}{42} - \frac{3}{42} + \frac{11}{42}) = 9 + \frac{5-3+11}{42} = 9 + \frac{13}{42} = 9\frac{13}{42}\)

в) \(2\frac{1}{2} \cdot 48 + 3\frac{2}{3} : 18 = \frac{5}{2} \cdot 48 + \frac{11}{3} : 18 = \frac{5 \cdot 48}{2} + \frac{11}{3 \cdot 18} = 5 \cdot 24 + \frac{11}{54} = 120 + \frac{11}{54} = 120\frac{11}{54}\)

г) \(1 - \frac{8}{17} = \frac{17}{17} - \frac{8}{17} = \frac{17-8}{17} = \frac{9}{17}\)