Решебник по математике 6 класс Виленкин ФГОС Часть 1, 2 Часть 2. П. 4. Действия с рациональными числами Задание 298

\[\boxed{\text{4.\ 298}}\]

\[1)\ \frac{\frac{3}{8} \cdot \frac{8}{21} + \frac{21}{22}\ :\frac{7}{66}}{8\ :0,4 - 19,36} =\]

\[= \frac{\frac{1}{7} + \frac{21}{22} \cdot \frac{66}{7}}{20 - 19,36} = \frac{\frac{1}{7} + 9}{0,64} = \frac{9\frac{1}{7}}{0,64} =\]

\[= \frac{64}{7}\ :\frac{64}{100} =\]

\[= \frac{64}{7} \cdot \frac{100}{64} = \frac{100}{7} = 14\frac{2}{7}\]

\[2)\ \frac{\left( 15 - 9\frac{2}{3} \right)\ :\frac{2}{3}}{\left( 19\frac{2}{3} - 11\frac{7}{9} \right) \cdot \frac{9}{71}} =\]

\[= \frac{5\frac{1}{3} \cdot \frac{3}{2}}{\left( 19\frac{6}{9} - 11\frac{7}{9} \right) \cdot \frac{9}{71}} =\]

\[= \frac{\frac{16}{3} \cdot \frac{3}{2}}{\left( 18\frac{15}{9} - 11\frac{7}{9} \right) \cdot \frac{9}{71}} =\]

\[= \frac{8}{7\frac{8}{9} \cdot \frac{9}{71}} = \frac{8}{\frac{71}{9} \cdot \frac{9}{71}} = \frac{8}{1} = 8\]