Вычислите: 1 5/6 : (2/3 − 2/7).

\[1\frac56=\frac{11}{6},\qquad \frac23-\frac27=\frac8{21}.\]

\[\frac{11}{6}:\frac8{21}=\frac{11}{6}\cdot\frac{21}{8}=\frac{77}{16}=4\frac{13}{16}.\]

Ответ: \(4\frac{13}{16}\).