Answer
$\sum_{i=1}^{20}\dfrac{i+1}{i+2}$
Work Step by Step
In order to set up the summation notation, we must calculate that value which keeps constantly changing. That value will be designated as the $i$ term. The remaining terms would remain constant in the summation notation.
Thus, we get the summation notation as: $\sum_{i=1}^{20}\dfrac{i+1}{i+2}$
