Решебник по математике 5 класс Мерзляк ФГОС Задание 1040

\[\boxed{\mathbf{1040\ (1040)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]

\[\frac{6,4 + y}{2} = 8,5\ \ \ \ \ \ \]

\[6,4 + y = 8,5 \cdot 2\]

\[6,4 + y = 17\]

\[y = 17 - 6,4\]

\[y = 10,6.\]

\[Ответ:\ \ 10,6.\]

\[\boxed{\mathbf{1040}\mathbf{.}\mathbf{\ }}\]

\[1)\ \left( 9\frac{3}{7} + 2\frac{9}{16} \right) - 5\frac{3}{7} =\]

\[= \left( 9\frac{3}{7} - 5\frac{3}{7} \right) + 2\frac{9}{16} =\]

\[= 4 + 2\frac{9}{16} = 6\frac{9}{16}\]

\[2)\ \left( 4\frac{5}{8} + 1\frac{6}{11} \right) - \frac{6}{11} =\]

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

\[= 5\frac{5}{8}\]

\[3)\ 10\frac{5}{14} - \left( 3\frac{5}{14} + 2\frac{9}{34} \right) =\]

\[= \left( 10\frac{5}{14} - 3\frac{5}{14} \right) - 2\frac{9}{34} =\]

\[= 7 - 2\frac{9}{34} =\]

\[= 6\frac{34}{34} - 2\frac{9}{34} = 4\frac{25}{34}\]

\[4)\ 7\frac{1}{7} - \left( 2\frac{6}{13} + 3\frac{1}{7} \right) =\]

\[= \left( 7\frac{1}{7} - 3\frac{1}{7} \right) - 2\frac{6}{13} =\]

\[= 4 - 2\frac{6}{13} =\]

\[= 3\frac{13}{13} - 2\frac{6}{13} = 1\frac{7}{13}\]