Вопрос:

б) \((6\frac{3}{8}\cdot1\frac{7}{11}-2\frac{3}{8}):1\frac{1}{4}+\frac{2}{5}\)

Ответ:

\[\left(6\frac{3}{8}\cdot1\frac{7}{11}-2\frac{3}{8}\right):1\frac{1}{4}+\frac{2}{5}\]

\[6\frac{3}{8}=\frac{51}{8},\qquad 1\frac{7}{11}=\frac{18}{11},\qquad 2\frac{3}{8}=\frac{19}{8},\qquad 1\frac{1}{4}=\frac{5}{4}\]

\[\frac{51}{8}\cdot\frac{18}{11}-\frac{19}{8}=\frac{459}{44}-\frac{19}{8}=\frac{918}{88}-\frac{209}{88}=\frac{709}{88}\]

\[\frac{709}{88}:\frac{5}{4}=\frac{709}{88}\cdot\frac{4}{5}=\frac{709}{110}\]

\[\frac{709}{110}+\frac{2}{5}=\frac{709}{110}+\frac{44}{110}=\frac{753}{110}=6\frac{93}{110}\]

Ответ: \(6\frac{93}{110}\).