Найдите значение выражения:
1) 43 + (−60) + 12 + 39 + (−21);
2) −1,23 + 2,14 + 7,38 + (−5,77) + 1,62;
3) $-\frac{3}{7} + \frac{14}{19} + (-\frac{4}{7}) + 3\frac{5}{19}$;
4) $-\frac{5}{18} + (-\frac{4}{81}) + \frac{7}{18} + \frac{13}{81}$;
5) $-3\frac{5}{11} + 1\frac{3}{8} + 2\frac{5}{16} + (-4\frac{6}{11})$.
43 + (−60) + 12 + 39 + (−21) = (43 + 12 + 39) + (−60 + (−21)) = 94 + (−81) = 13
−1,23 + 2,14 + 7,38 + (−5,77) + 1,62 = (7,38 + 1,62) + (−5,77 + (−1,23)) + 2,14 = 9 + 2,14 + (−7) = 11,14 − 7 = 4,14
$-\frac{3}{7} + \frac{14}{19} + (-\frac{4}{7}) + 3\frac{5}{19} = (-\frac{3}{7} + (-\frac{4}{7})) + (\frac{14}{19} + 3\frac{5}{19}) = -\frac{7}{7} + 3\frac{19}{19} = -1 + 4 = 3$
$-\frac{5}{18} + (-\frac{4}{81}) + \frac{7}{18} + \frac{13}{81} = (-\frac{5}{18} + \frac{7}{18}) + (-\frac{4}{81} + \frac{13}{81}) = \frac{2}{18} + \frac{9}{81} = \frac{1}{9} + \frac{1}{9} = \frac{2}{9}$
$-3\frac{5}{11} + 1\frac{3}{8} + 2\frac{5}{16} + (-4\frac{6}{11}) = (-3\frac{5}{11} + (-4\frac{6}{11})) + (1\frac{3}{8} + 2\frac{5}{16}) = -7\frac{11}{11} + (1\frac{6}{16} + 2\frac{5}{16}) = -8 + 3\frac{11}{16} = -7\frac{16}{16} + 3\frac{11}{16} = -4\frac{5}{16}$
Пожауйста, оцените решение
