$\left ( \frac{1}{3}+\frac{2}{3} \right ) +\left ( \frac{1}{4}+\frac{2}{4} +\frac{3}{4} \right)+\left ( \frac{1}{5}+\frac{2}{5} +\frac{3}{5}+\frac{4}{5}\right )+...+\left ( \frac{1}{100}+...+\frac{99}{100} \right )$