\(a.\dfrac{3}{7}+\left(\dfrac{-5}{2}\right)+\left(\dfrac{-3}{5}\right)\\ =\dfrac{30}{70}+\dfrac{-175}{70}+\dfrac{-42}{70}\\ =\dfrac{30-175-42}{70}\\ =\dfrac{-187}{70}\\ b.\left(\dfrac{-4}{3}\right)+\left(\dfrac{-2}{5}\right)+\left(\dfrac{-3}{2}\right)\\ =\dfrac{-40}{30}+\dfrac{-12}{30}+\dfrac{-45}{30}\\ =\dfrac{-40-12-45}{30}\\ =\dfrac{-97}{30}\\ c.\dfrac{4}{5}-\left(\dfrac{2}{7}\right)-\dfrac{7}{10}\\ =\dfrac{4}{5}+\dfrac{2}{7}-\dfrac{7}{10}\\ =\dfrac{56}{70}+\dfrac{20}{70}-\dfrac{49}{70}\\ =\dfrac{56+20-49}{70}\\ =\dfrac{27}{70}\\ d.\dfrac{2}{3}-\left[\left(-\dfrac{7}{4}\right)+\left(\dfrac{1}{2}+\dfrac{3}{8}\right)\right]\\ =\dfrac{2}{3}-\left(\dfrac{-7}{4}+\dfrac{1}{2}+\dfrac{3}{8}\right)\\ =\dfrac{2}{3}-\left(\dfrac{-14}{8}+\dfrac{4}{8}+\dfrac{3}{8}\right)\\ =\dfrac{2}{3}-\dfrac{-7}{8}\\ =\dfrac{2}{3}+\dfrac{7}{8}\\ =\dfrac{37}{24}\)
