Simplify :

$1 ÷ \dfrac{4}{7} - \dfrac{1}{3}$ of $3\dfrac{3}{4} + \dfrac{1}{2} ÷ 3$

$\Rightarrow 1 ÷ \dfrac{4}{7} - \Big(\dfrac{1}{3} \text{ of } 3\dfrac{3}{4}\Big) + \dfrac{1}{2} ÷ 3\\[1em] \Rightarrow 1 ÷ \dfrac{4}{7} - \Big(\dfrac{1}{3} \times 3\dfrac{3}{4}\Big) + \dfrac{1}{2} ÷ 3\\[1em] \Rightarrow 1 ÷ \dfrac{4}{7} - \dfrac{1}{3} \times \dfrac{15}{4} + \dfrac{1}{2} ÷ 3\\[1em] \Rightarrow 1 ÷ \dfrac{4}{7} - \dfrac{1 \times 15}{3 \times 4} + \dfrac{1}{2} ÷ 3\\[1em] \Rightarrow 1 ÷ \dfrac{4}{7} - \dfrac{15}{12} + \dfrac{1}{2} ÷ 3\\[1em] \Rightarrow 1 ÷ \dfrac{4}{7} - \dfrac{5}{4} + \dfrac{1}{2} ÷ 3\\[1em] \Rightarrow 1 \times \dfrac{7}{4} - \dfrac{5}{4} + \dfrac{1}{2} \times \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{7}{4} - \dfrac{5}{4} + \dfrac{1 \times 1}{2 \times 3}\\[1em] \Rightarrow \dfrac{7}{4} - \dfrac{5}{4} + \dfrac{1}{6}\\[1em] \Rightarrow \dfrac{7 \times 3}{4 \times 3} - \dfrac{5 \times 3}{4 \times 3} + \dfrac{1 \times 2}{6 \times 2}\\[1em] \Rightarrow \dfrac{21}{12} - \dfrac{15}{12} + \dfrac{2}{12}\\[1em] \Rightarrow \dfrac{21 - 15 + 2}{12}\\[1em] \Rightarrow \dfrac{21 - 13}{12}\\[1em] \Rightarrow \dfrac{8}{12}\\[1em] \Rightarrow \dfrac{2}{3}$

Hence, $1 ÷ \dfrac{4}{7} - \dfrac{1}{3}$ of $3\dfrac{3}{4} + \dfrac{1}{2} ÷ 3 = \dfrac{2}{3}$.