Решебник по математике 6 класс Мерзляк ФГОС Задание 991

\[\boxed{\mathbf{991\ (981).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[1)\ a = 9,6;\ \ b = - 5,7:\]

\[7,44 + a + ( - 3,5) + ( - 5,44) +\]

\[+ ( - 12,5) + b =\]

\[= 7,44 + 9,6 - 3,5 - 5,44 -\]

\[- 12,5 - 5,7 = 2 + 3,9 - 16 =\]

\[= - 10,1\]

\[2)\ p = - 2\frac{19}{30};\ \ k = 9:\]

\[- 5\frac{9}{35} + p + 4\frac{11}{28} + 6\frac{2}{35} +\]

\[+ \left( - 5\frac{18}{28} \right) + k =\]

\[= - 5\frac{9}{35} - 2\frac{19}{30} + 4\frac{11}{28} + 6\frac{2}{35} -\]

\[- 5\frac{18}{28} + 9 = \frac{28}{35} - 1\frac{7}{28} + 6\frac{11}{30} =\]

\[= \frac{4}{5} - 1\frac{1}{4} + 6\frac{11}{30} = \frac{48}{60} - 1\frac{15}{60} +\]

\[+ 6\frac{22}{60} = 5\frac{7}{60} + \frac{48}{60} = 5\frac{55}{60} =\]

\[= 5\frac{11}{12}\]