# Question #c0cfe

${\sum}_{\text{n=3}}^{7} 9 + 4 {n}^{2} + 4 =$
${\sum}_{\text{n=3}}^{7} 4 {n}^{2} + 13$
These are 5 terms to be added. And you are on the right way, but you forgot to add the $5 \cdot 13 = 65$
Actually, I think it strange that the $9$ and $4$ are separated. I suspect one of them had a $n$ attached to it in the original problem.
You always calculate the full expression, for every value of $n$ from $3$ up to (and including) $7$.