ГДЗ по математике 6 класс Дорофеев Задание 749

\[\boxed{\mathbf{749\ (749)}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[\textbf{а)} - 9 + 12 + ( - 8) = \left( - 9 + ( - 8) \right) + 12 = - 17 + 12 = - 5\]

\[\textbf{б)}\ 10 + ( - 7) + ( - 6) = 10 + \left( ( - 7) + ( - 6) \right) = 10 + ( - 13) = - 3\]

\[\textbf{в)}\ 5 + ( - 6) + ( - 9) = 5 + \left( ( - 6) + ( - 9) \right) = 5 + ( - 15) = - 10\]

\[\textbf{г)} - 10 + 19 + ( - 10) = \left( - 10 + ( - 10) \right) + 19 = - 20 + 19 = - 1\]

\[\textbf{д)}\ 9 + ( - 15) + 14 = (9 + 14) + ( - 15) = 23 + ( - 15) = 8\]

\[\textbf{е)} - 20 + ( - 4) + 9 = \left( - 20 + ( - 4) \right) + 9 = - 24 + 9 = - 15\]