26 Раскройте скобки и вычислите: a) 7,646 (6,9 – 2,054); 6) 4,17+ (9,182 – 4,17); ;r) (3 + 2)-(2+1); д) -(3,69 - 6)-(1,31-8); e) -(+2,43) - (-5,93-).

Ответ: a) 2,708; б) 9,182; г) 1\(\frac{31}{104}\); д) 10\(\frac{1}{13}\); е) 3,14\(\frac{1}{2}\)

1. а) 7,646 - (6,9 – 2,054) = 7,646 - 6,9 + 2,054 = 0,746 + 2,054 = 2,700
2. б) 4,17 + (9,182 – 4,17) = 4,17 + 9,182 - 4,17 = 9,182
3. 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\(\frac{2}{13}\)) = (2\(\frac{13}{8}\) - 2\(\frac{7}{8}\)) + (1\(\frac{15}{13}\) - 1\(\frac{2}{13}\)) = \(\frac{6}{8}\) + \(\frac{13}{13}\) = \(\frac{3}{4}\) + 1 = 1\(\frac{3}{4}\)
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
5. е) -(\(\frac{5}{8}\) + 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

Ответ: a) 2,708; б) 9,182; г) 1\(\frac{31}{104}\); д) 10\(\frac{1}{13}\); е) 3,14\(\frac{1}{2}\)