ГДЗ по математике 6 класс Мерзляк Задание 990

\[\boxed{\mathbf{990\ (980).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[1)\ 43 + ( - 60) + 12 + 39 +\]

\[+ ( - 21) = 43 - 60 + 12 +\]

\[+ 39 - 21 = 94 - 81 = 13\]

\[2) - 1,23 + 2,14 + 7,38 +\]

\[+ ( - 5,77) + 1,62 =\]

\[= - 1,23 + 2,14 + 7,38 - 5,77 +\]

\[+ 1,62 = - 7 + 11,14 = 4,14\]

\[3) - \frac{3}{7} + \frac{14}{19} + \left( - \frac{4}{7} \right) + 3\frac{5}{19} =\]

\[= - \frac{3}{7} + \frac{14}{19} - \frac{4}{7} + 3\frac{5}{19} =\]

\[= - \frac{7}{7} + 3\frac{19}{19} =\]

\[= - 1 + 4 = 3\]

\[4) - \frac{5}{18} + \left( - \frac{4}{81} \right) + \frac{7}{18} + \frac{13}{81} =\]

\[= \frac{2}{18} - \frac{4}{81} + \frac{13}{81} = \frac{1}{9} + \frac{9}{81} =\]

\[= \frac{1}{9} + \frac{1}{9} = \frac{2}{9}\]

\[5) - 3\frac{5}{11} + 1\frac{3}{8} + 2\frac{5}{16} +\]

\[+ \left( - 4\frac{6}{11} \right) = - 3\frac{5}{11} + 1\frac{3}{8} +\]

\[+ 2\frac{5}{16} - 4\frac{6}{11} =\]

\[= - 7\frac{11}{11} + 1\frac{6}{16} + 2\frac{5}{16} =\]

\[= - 8 + 3\frac{11}{16} = - 4\frac{5}{16}\]