16. 2 1/3 × 3/4 + (3 1/2 − 1 5/6) ÷ 2/3 =

Преобразуем смешанные числа:

\[2\frac{1}{3}\cdot\frac{3}{4}+\left(3\frac{1}{2}-1\frac{5}{6}\right)\div\frac{2}{3}=\frac{7}{3}\cdot\frac{3}{4}+\left(\frac{7}{2}-\frac{11}{6}\right)\cdot\frac{3}{2}.\]

\[\frac{7}{3}\cdot\frac{3}{4}=\frac{7}{4},\qquad \frac{7}{2}-\frac{11}{6}=\frac{21}{6}-\frac{11}{6}=\frac{10}{6}=\frac{5}{3}.\]

\[\frac{7}{4}+\frac{5}{3}\cdot\frac{3}{2}=\frac{7}{4}+\frac{5}{2}=\frac{7}{4}+\frac{10}{4}=\frac{17}{4}=4\frac{1}{4}.\]

Ответ: \(4\frac{1}{4}\).