Question

Вычислите рациональным способом: ​

Answer 1

Решение:

а) -18 +  16 -2 + 4 = (16 +4) + (-18-2) = 20 + (-20) = 0;

б) 25 - 13 + 5 - 7 = (25 + 5) + (-13 - 7) = 30 + (-20) = 10;

а) $\frac{3}{14} - \frac{9}{17} - \frac{8}{17} +\frac{1}{14} = (\frac{3}{14} + \frac{1}{14} ) - ( \frac{9}{17} + \frac{8}{17}) = \frac{4}{14} - \frac{17}{17} = \frac{2}{7} - 1 = - (\frac{7}{7}- \frac{2}{7} ) = - \frac{5}{7} .$;

б) $\frac{9}{19} - \frac{4}{5} - \frac{3}{5} + \frac{10}{19} = (\frac{9}{19} + \frac{10}{19}) - ( \frac{4}{5} + \frac{3}{5}) = \frac{19}{19} - \frac{7}{5} = 1 - 1\frac{2}{5} = - (1\frac{2}{5} - 1) = - \frac{2}{5} .$