5.26 Раскройте скобки и вычислите: a) 7,646 - (6,9 – 2,054); б) 4,17 + (9,182 – 4,17); в) 4/9 + (1/9 – 2/3); г) (3 5/8 + 2 2/13) – (2 7/8 + 1 2/13); д) – (3,69 – 6 2/13) – (1,31 – 8 11/13); e) – (5/8 + 2,43) – (-5,93 – 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 + 4,17 - 4,17 = **9,182** в) $\frac{4}{9} + (\frac{1}{9} - \frac{2}{3}) = \frac{4}{9} + \frac{1}{9} - \frac{2}{3} = \frac{4}{9} + \frac{1}{9} - \frac{6}{9} = \frac{5}{9} - \frac{6}{9} = \frac{-1}{9} = **-\frac{1}{9}**$ 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}) = (3 - 2 + \frac{5}{8} - \frac{7}{8}) + (2 - 1 + \frac{2}{13} - \frac{2}{13}) = 1 - \frac{2}{8} + 1 + 0 = 1 - \frac{1}{4} + 1 = 2 - \frac{1}{4} = \frac{8}{4} - \frac{1}{4} = **\frac{7}{4}** или **1,75** д) – (3,69 – 6 $\frac{2}{13}$) – (1,31 – 8 $\frac{11}{13}$) = -3,69 + 6 $\frac{2}{13}$ - 1,31 + 8 $\frac{11}{13}$ = (6 $\frac{2}{13}$ + 8 $\frac{11}{13}$) + (-3,69 - 1,31) = 14 $\frac{13}{13}$ - 5 = 14 + 1 - 5 = 15 - 5 = **10** e) – ($\frac{5}{8}$ + 2,43) – (-5,93 – $\frac{1}{4}$) = -$\frac{5}{8}$ - 2,43 + 5,93 + $\frac{1}{4}$ = -0,625 - 2,43 + 5,93 + 0,25 = -3,055 + 6,18 = **3,125**