Ответ:

Преобразуем смешанные числа: \(2\frac{4}{15}=\frac{34}{15}\), \(4\frac{11}{14}=\frac{67}{14}\).

\(4:\frac{20}{23}=4\cdot\frac{23}{20}=\frac{23}{5}\).

\(\frac{2}{7}-\frac{67}{14}=\frac{4}{14}-\frac{67}{14}=-\frac{63}{14}=-\frac{9}{2}\).

\(\frac{34}{15}\cdot\left(-\frac{9}{2}\right)=-\frac{51}{5}\).

\(\frac{23}{5}-\frac{51}{5}=-\frac{28}{5}\).

Ответ: \(-\frac{28}{5}\).