Show that the sum of the series is greater than 24 $$\frac{1}{\sqrt{1}+\sqrt{3}}+\frac{1}{\sqrt{5}+\sqrt{7}}+\frac{1}{\sqrt{9}+\sqrt{11}} +\cdots+\frac{1}{\sqrt{9997}+\sqrt{9999}} > 24$$
I see that
$\frac{1}{\sqrt{3}+\sqrt{1}}\cdot \frac{\sqrt{3}-\sqrt{1}}{\sqrt{3}-\sqrt{1}}=\frac{\sqrt{3}-\sqrt{1}}{2}$
In each term, the denominator is 2 so the series becomes $\frac{1}{2}\sum^{2499}_{n=0}[\sqrt{4n+3}-\sqrt{4n+1}]$