\(=\left(\dfrac{1}{2}+\dfrac{-1}{2}\right)+\left(\dfrac{-1}{3}+\dfrac{1}{3}\right)+\left(\dfrac{1}{4}+\dfrac{-1}{4}\right)+\left(\dfrac{-1}{5}+\dfrac{1}{5}\right)+\left(\dfrac{1}{6}+\dfrac{-1}{6}\right)+\left(\dfrac{-1}{7}+\dfrac{1}{7}\right)+\dfrac{1}{8}\)

\(=0+0+0+0+0+0+\dfrac{1}{8}\)

\(=\dfrac{1}{8}\)