a) \(\dfrac{3}{4}\times\left(\dfrac{5}{6}+\dfrac{2}{3}\right)=\dfrac{3}{4}\times\left(\dfrac{10}{12}+\dfrac{8}{12}\right)=\dfrac{3}{4}\times\dfrac{18}{12}=\dfrac{3}{4}\times\dfrac{3}{4}=\dfrac{9}{8}\)
b) \(\dfrac{3}{2}-\dfrac{2}{3}\div2=\dfrac{3}{2}-\dfrac{1}{3}=\dfrac{9}{6}-\dfrac{2}{6}=\dfrac{7}{6}\)