5.26 Раскройте скобки и вычислите: a) 7,646 - (6,9 – 2,054); б) 4,17 + (9,182 – 4,17); в) \frac{4}{9} + (\frac{1}{9} - \frac{2}{3}); г) (3\frac{5}{8} + 2\frac{2}{13}) - (2\frac{7}{8} + 1\frac{2}{13}); д) -(3,69 - 6\frac{2}{13}) - (1,31 - 8\frac{11}{13}); e) -(\frac{5}{8} + 2,43) - (-5,93 - \frac{1}{4}).

a) 7,646 - (6,9 – 2,054) = 7,646 - 6,9 + 2,054 = 0,746 + 2,054 = 2,8

б) 4,17 + (9,182 – 4,17) = 4,17 + 9,182 - 4,17 = 9,182

в) \frac{4}{9} + (\frac{1}{9} - \frac{2}{3}) = \frac{4}{9} + \frac{1}{9} - \frac{2}{3} = \frac{5}{9} - \frac{6}{9} = -\frac{1}{9}

г) (3\frac{5}{8} + 2\frac{2}{13}) - (2\frac{7}{8} + 1\frac{2}{13}) = 3\frac{5}{8} + 2\frac{2}{13} - 2\frac{7}{8} - 1\frac{2}{13} = (3\frac{5}{8} - 2\frac{7}{8}) + (2\frac{2}{13} - 1\frac{2}{13}) = \frac{29}{8} + \frac{28}{13} - \frac{23}{8} - \frac{15}{13} = (\frac{29}{8} - \frac{23}{8}) + (\frac{28}{13} - \frac{15}{13}) = \frac{6}{8} + \frac{13}{13} = \frac{3}{4} + 1 = 1\frac{3}{4}

д) -(3,69 - 6\frac{2}{13}) - (1,31 - 8\frac{11}{13}) = -3,69 + 6\frac{2}{13} - 1,31 + 8\frac{11}{13} = (-3,69 - 1,31) + (6\frac{2}{13} + 8\frac{11}{13}) = -5 + 14\frac{13}{13} = -5 + 15 = 10

e) -(\frac{5}{8} + 2,43) - (-5,93 - \frac{1}{4}) = -\frac{5}{8} - 2,43 + 5,93 + \frac{1}{4} = -\frac{5}{8} + \frac{1}{4} - 2,43 + 5,93 = -\frac{5}{8} + \frac{2}{8} + 3,5 = -\frac{3}{8} + 3,5 = -0,375 + 3,5 = 3,125