1. Найдите значение выражения 1) \(\frac{19}{28} + \frac{16}{28} - \frac{17}{28}\); 2) \(4 \frac{11}{14} - 2 \frac{5}{14} + 1 \frac{3}{14}\); 3) \(1 - \frac{8}{17}\); 4) \(4 \frac{5}{9} - 2 \frac{8}{9}\); 5) \(4 \frac{4}{9} \cdot 2 \frac{5}{8}\); 6) \(\frac{8}{13} : 4\); 7) \(2 \frac{3}{8} \cdot 3 \frac{1}{5} : \frac{19}{20}\);

1) \(\frac{19}{28} + \frac{16}{28} - \frac{17}{28} = \frac{19 + 16 - 17}{28} = \frac{35 - 17}{28} = \frac{18}{28} = \frac{9}{14}\)
2) \(4 \frac{11}{14} - 2 \frac{5}{14} + 1 \frac{3}{14} = (4 - 2 + 1) + (\frac{11}{14} - \frac{5}{14} + \frac{3}{14}) = 3 + \frac{11 - 5 + 3}{14} = 3 + \frac{9}{14} = 3 \frac{9}{14}\)
3) \(1 - \frac{8}{17} = \frac{17}{17} - \frac{8}{17} = \frac{17 - 8}{17} = \frac{9}{17}\)
4) \(4 \frac{5}{9} - 2 \frac{8}{9} = 4 \frac{5}{9} - 2 \frac{8}{9} = 3 \frac{14}{9} - 2 \frac{8}{9} = (3 - 2) + (\frac{14}{9} - \frac{8}{9}) = 1 + \frac{14 - 8}{9} = 1 + \frac{6}{9} = 1 \frac{6}{9} = 1 \frac{2}{3}\)
5) \(4 \frac{4}{9} \cdot 2 \frac{5}{8} = \frac{4 \cdot 9 + 4}{9} \cdot \frac{2 \cdot 8 + 5}{8} = \frac{36 + 4}{9} \cdot \frac{16 + 5}{8} = \frac{40}{9} \cdot \frac{21}{8} = \frac{5}{3} \cdot \frac{7}{1} = \frac{35}{3} = 11 \frac{2}{3}\)
6) \(\frac{8}{13} : 4 = \frac{8}{13} : \frac{4}{1} = \frac{8}{13} \cdot \frac{1}{4} = \frac{2}{13} \cdot \frac{1}{1} = \frac{2}{13}\)
7) \(2 \frac{3}{8} \cdot 3 \frac{1}{5} : \frac{19}{20} = \frac{2 \cdot 8 + 3}{8} \cdot \frac{3 \cdot 5 + 1}{5} : \frac{19}{20} = \frac{16 + 3}{8} \cdot \frac{15 + 1}{5} : \frac{19}{20} = \frac{19}{8} \cdot \frac{16}{5} : \frac{19}{20} = \frac{19}{8} \cdot \frac{16}{5} \cdot \frac{20}{19} = \frac{1}{2} \cdot \frac{4}{1} \cdot \frac{4}{1} = \frac{1}{1} \cdot \frac{2}{1} \cdot \frac{4}{1} = 8\)