Calculate \( \sum \limits _{i=100}^{200} i \)

5th Ed: Like 35

\( a_1 = 100 \)
\( d = 1 \)
\( n=101 \)
\( S_{100} = \frac{101}{2} \left ( 2(100) + 100(1) \right ) =\frac{101}{2}(300)=\frac{30300}{2}=15150\)