[laTEX]\frac{2}{3.5} = \frac{1}{3}- \frac{1}{5} \\ \\ \frac{2}{5.7} = \frac{1}{5} - \frac{1}{7} \\ \\ .................................... \\ \\ \frac{2}{97.99} = \frac{1}{97} - \frac{1}{99} \\ \\ \Rightarrow \frac{2}{3.5}+\frac{2}{5.7} +.......+ \frac{2}{97.99} = \frac{1}{3} -\frac{1}{5} +\frac{1}{5}- \frac{1}{7} +.........+\frac{1}{97}- \frac{1}{99} \\ \\ = \frac{1}{3} - \frac{1}{99} = \frac{32}{99}[/laTEX]