8. (11/15 + 1/4) · 1 7/23 − (3 1/3 − 1 1/2) : 1 1/7

\(\frac{11}{15}+\frac14=\frac{59}{60}\), поэтому \(\frac{59}{60}\cdot1\frac7{23}=\frac{59}{60}\cdot\frac{30}{23}=\frac{59}{46}\).

\(3\frac13-1\frac12=\frac{11}{6}\), поэтому \(\frac{11}{6}:1\frac17=\frac{11}{6}\cdot\frac78=\frac{77}{48}\).

\(\frac{59}{46}-\frac{77}{48}=\frac{1416-1771}{1104}=-\frac{355}{1104}\).

Ответ: \(-\frac{355}{1104}\).