Найдите значение выражения:
1) −78 + 36 + 19 + (−22) + (−25);
2) 0,74 + (−9,39) + 3,26 + (−10,61) + 5,25;
3) $\frac{7}{16} + (-\frac{11}{42}) + (-\frac{9}{16}) + \frac{17}{42}$;
4) $-\frac{9}{40} + \frac{13}{50} + (-\frac{23}{50}) + \frac{19}{40}$;
5) $-3\frac{31}{36} + (-1\frac{17}{24}) + 5\frac{4}{36} + (-2\frac{4}{24})$.
−78 + 36 + 19 + (−22) + (−25) = (−78 + (−22)) + (36 + 19 − 25) = −100 + 30 = −70
0,74 + (−9,39) + 3,26 + (−10,61) + 5,25 = (−10,61 + (−9,39)) + (0,74 + 3,26) + 5,25 = −20 + 4 + 5,25 = −20 + 9,25 = −10,75
$\frac{7}{16} + (-\frac{11}{42}) + (-\frac{9}{16}) + \frac{17}{42} = (\frac{7}{16} + (-\frac{9}{16})) + (\frac{17}{42} - \frac{11}{42}) = -\frac{2}{16} + \frac{6}{42} = -\frac{1}{8} + \frac{1}{7} = -\frac{7}{56} + \frac{8}{56} = \frac{1}{56}$
$-\frac{9}{40} + \frac{13}{50} + (-\frac{23}{50}) + \frac{19}{40} = (\frac{19}{40} - \frac{9}{40}) + (-\frac{23}{50} + \frac{13}{50}) = \frac{10}{40} + (-\frac{10}{50}) = \frac{1}{4} + (-\frac{1}{5}) = \frac{5}{20} + (-\frac{4}{20}) = \frac{1}{20}$
$-3\frac{31}{36} + (-1\frac{17}{24}) + 5\frac{4}{36} + (-2\frac{4}{24}) = (-3\frac{31}{36} + 4\frac{40}{36}) + (-1\frac{17}{24} + (-2\frac{4}{24})) = 1\frac{9}{36} + (-3\frac{21}{24}) = 1\frac{1}{4} + (-3\frac{7}{8}) = 1\frac{2}{8} + (-3\frac{7}{8}) = -2\frac{5}{8}$
Пожауйста, оцените решение
