Finding the value of $ \sum_{n=5}^{204} (n - 2) $ Is there a generalized formula for finding a sum such as this one? I'm going over an old quiz for a programming class but I'm not able to solve it:
$$ \sum_{n=5}^{204} (n - 2) $$
I know this is probably dead simple, but I'm seriously lacking on the math side of computer science. 

the only thing that you have to kcon is that :
$$
\sum_{k=0}^{n} k = \frac{n(n+1)}{2}
$$
