г) 1 8/9 : (3 1/6 − 1 3/4) =

Преобразуем смешанные числа:

\(1\frac{8}{9}=\frac{17}{9}\), \(3\frac{1}{6}=\frac{19}{6}\), \(1\frac{3}{4}=\frac{7}{4}\).

\(3\frac{1}{6}-1\frac{3}{4}=\frac{19}{6}-\frac{7}{4}=\frac{38-21}{12}=\frac{17}{12}\).

\(\frac{17}{9}:\frac{17}{12}=\frac{17}{9}\cdot\frac{12}{17}=\frac{4}{3}=1\frac{1}{3}\).

Ответ: \(1\frac{1}{3}\)