Решебник по математике 6 класс Мерзляк ФГОС Задание 321

\[\boxed{\mathbf{321\ (322).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[\frac{1}{31} + \frac{1}{32} + \frac{1}{33} + .. + \frac{1}{39} + \frac{1}{40} > \frac{1}{4}\]

\[\frac{1}{31} > \frac{1}{40};\ \ \frac{1}{32} > \frac{1}{40};\ \ \frac{1}{33} > \frac{1}{40};\ \]

\[\frac{1}{34} > \frac{1}{40};\ \ \frac{1}{35} > \frac{1}{40};\ \]

\[\frac{1}{36} > \frac{1}{40};\ \frac{1}{37} > \frac{1}{40};\ \ \frac{1}{38} > \frac{1}{40};\ \]

\[\ \frac{1}{39} > \frac{1}{40}\]

\[\frac{1}{31} + \frac{1}{32} + \frac{1}{33} + .. + \frac{1}{39} + \frac{1}{40} >\]

\[> \frac{1}{40} + \frac{1}{40} + \frac{1}{40} + .. + \frac{1}{40} + \frac{1}{40} =\]

\[= \frac{10}{40} = \frac{1}{4} \Longrightarrow верно,\ ч.т.д.\]

\[\boxed{\mathbf{321\ (}\mathbf{с}\mathbf{).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[\frac{1}{10} + \frac{1}{11} + \frac{1}{12} + .. + \frac{1}{18} > \frac{1}{2}\]

\[\frac{1}{10} > \frac{1}{18};\ \ \frac{1}{11} > \frac{1}{18};\ \ \frac{1}{12} > \frac{1}{18};\ \]

\[\ \frac{1}{13} > \frac{1}{18};\ \frac{1}{14} > \frac{1}{18};\ \frac{1}{15} > \frac{1}{18};\ \]

\[\frac{1}{16} > \frac{1}{18};\ \ \frac{1}{17} > \frac{1}{18}\]

\[\frac{1}{1} + \frac{1}{1} + .. + \frac{1}{18} > \frac{1}{18} + \frac{1}{18} + .. + \frac{1}{18} =\]

\[= \frac{9}{18} = \frac{1}{2} \Longrightarrow верно,\ ч.\ т.д.\]

\[\boxed{\mathbf{321}\mathbf{.}}\]

\[1)\ 10\ :3 = \frac{10}{3} = 3\frac{1}{3}\]

\[2)\ 20\ :13 = \frac{20}{13} = 1\frac{7}{13}\]

\[3)\ 72\ :19 = \frac{72}{19} = 3\frac{15}{19}\]

\[4)\ 423\ :50 = \frac{423}{50} = 8\frac{23}{50}\]