4) \(\left(3\frac{1}{4}+3\frac{5}{6}\right):\left(5\frac{3}{4}-3\frac{2}{3}\right)\)

Числитель: \(3\frac{1}{4}+3\frac{5}{6}=\frac{13}{4}+\frac{23}{6}=\frac{39+46}{12}=\frac{85}{12}\).

Знаменатель: \(5\frac{3}{4}-3\frac{2}{3}=\frac{23}{4}-\frac{11}{3}=\frac{69-44}{12}=\frac{25}{12}\).

Делим: \(\frac{85}{12}:\frac{25}{12}=\frac{85}{25}=\frac{17}{5}=3\frac{2}{5}\).

Ответ: \(3\frac{2}{5}\)