ГДЗ по математике 6 класс Мерзляк ФГОС Задание 421

\[\boxed{\mathbf{421}.}\]

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

\[\frac{1}{2} = \frac{9}{18}\]

\[\frac{9}{18} = \frac{1}{18} + \frac{1}{18} + \frac{1}{18} + \ldots + \frac{1}{18}\]

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

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

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

\[\frac{1}{10} + \frac{1}{11} + \frac{1}{12} + \ldots + \frac{1}{18} > \frac{9}{18}\]

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

\[Что\ и\ требовалось\ доказать.\]