\(\left(6-\dfrac{5}{3}+\dfrac{1}{2}\right)-\left(3+\dfrac{2}{3}-\dfrac{3}{2}\right)-\left(5+\dfrac{5}{2}-\dfrac{7}{3}\right)\\ =\left(6-3-5\right)-\left(\dfrac{5}{3}+\dfrac{2}{3}-\dfrac{7}{3}\right)+\left(\dfrac{1}{2}+\dfrac{3}{2}-\dfrac{5}{2}\right)\\ =-2-0-\dfrac{1}{2}=-\dfrac{5}{2}\)