ГДЗ по математике 6 класс Мерзляк Задание 989

\[\boxed{\mathbf{989\ (979).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[1) - 78 + 36 + 19 + ( - 22) +\]

\[+ ( - 25) = - 78 + 36 + 19 -\]

\[- 22 - 25 =\]

\[= - 100 + 55 - 25 = - 100 +\]

\[+ 30 = - 70\]

\[2)\ 0,74 + ( - 9,39) + 3,26 +\]

\[+ ( - 10,61) + 5,25 =\]

\[= 0,74 - 9,39 + 3,26 - 10,61 +\]

\[+ 5,25 = 4 - 20 + 5,25 =\]

\[= - 16 + 5,25 = - 10,75\]

\[3)\ \frac{7}{16} + \left( - \frac{11}{42} \right) + \left( - \frac{9}{16} \right) +\]

\[+ \frac{17}{42} = \frac{7}{16} - \frac{9}{16} - \frac{11}{42} + \frac{17}{42} =\]

\[= - \frac{2}{16} + \frac{6}{42} =\]

\[= - \frac{1}{8} + \frac{1}{7} = - \frac{7}{56} + \frac{8}{56} = \frac{1}{56}\]

\[4) - \frac{9}{40} + \frac{13}{50} + \left( - \frac{23}{50} \right) + \frac{19}{40} =\]

\[= - \frac{9}{40} + \frac{13}{50} - \frac{23}{50} + \frac{19}{40} =\]

\[= \frac{10}{40} - \frac{10}{50} =\]

\[= \frac{1}{4} - \frac{1}{5} = \frac{5}{20} - \frac{4}{20} = \frac{1}{20}\]

\[5) - 3\frac{31}{36} + \left( - 1\frac{17}{24} \right) + 5\frac{4}{36} +\]

\[+ \left( - 2\frac{4}{24} \right) = - 3\frac{31}{36} -\]

\[- 1\frac{17}{24} + 5\frac{4}{36} - 2\frac{4}{24} =\]

\[= 1\frac{9}{36} - 3\frac{21}{24} = 1\frac{1}{4} - 3\frac{7}{8} =\]

\[= 1\frac{2}{8} - 3\frac{7}{8} = - 2\frac{5}{8}\]