5.7 Раскройте скобки и найдите значение суммы: a) \frac{5}{9} + (\frac{4}{9} - \frac{7}{11}); б) 5\frac{3}{7} + (-\frac{3}{7} - \frac{8}{9}); в) 4,32 + (\frac{12}{13} - 3,32); г) \frac{7}{15} - (\frac{4}{15} - \frac{4}{5}); д) 6\frac{7}{9} - (3\frac{4}{9} + 2\frac{1}{3}); е) -9\frac{11}{12} - (\frac{1}{4} - \frac{5}{12}).

a) ( \frac{5}{9} + (\frac{4}{9} - \frac{7}{11}) = \frac{5}{9} + \frac{4}{9} - \frac{7}{11} = \frac{9}{9} - \frac{7}{11} = 1 - \frac{7}{11} = \frac{11}{11} - \frac{7}{11} = \frac{4}{11} ) б) ( 5\frac{3}{7} + (-\frac{3}{7} - \frac{8}{9}) = 5\frac{3}{7} - \frac{3}{7} - \frac{8}{9} = 5 - \frac{8}{9} = \frac{45}{9} - \frac{8}{9} = \frac{37}{9} = 4\frac{1}{9} ) в) ( 4,32 + (\frac{12}{13} - 3,32) = 4,32 + \frac{12}{13} - 3,32 = 1 + \frac{12}{13} = \frac{13}{13} + \frac{12}{13} = \frac{25}{13} = 1\frac{12}{13} ) г) ( \frac{7}{15} - (\frac{4}{15} - \frac{4}{5}) = \frac{7}{15} - \frac{4}{15} + \frac{4}{5} = \frac{3}{15} + \frac{12}{15} = \frac{15}{15} = 1 ) д) ( 6\frac{7}{9} - (3\frac{4}{9} + 2\frac{1}{3}) = 6\frac{7}{9} - 3\frac{4}{9} - 2\frac{1}{3} = 6\frac{7}{9} - 3\frac{4}{9} - 2\frac{3}{9} = 6\frac{7}{9} - 5\frac{7}{9} = 1 ) е) ( -9\frac{11}{12} - (\frac{1}{4} - \frac{5}{12}) = -9\frac{11}{12} - \frac{1}{4} + \frac{5}{12} = -9\frac{11}{12} - \frac{3}{12} + \frac{5}{12} = -9\frac{9}{12} = -9\frac{3}{4} )