Confused about two series I know this question is probably really trivial but I really just don't get it and was hoping someone could explain it to me.
With the following two series (where $c$ is a constant):
$$\sum_{i=0}^n\ c   = cn +c $$ 
$$\sum_{i=1}^n\ c   = cn $$ 
I just don't get why they equal what they do. I suppose I'm confused as there is no $i$ term in the expression to which I can substitute actual values into to get the terms, it is just the constant $c$. I just don't know how the terms $cn$ and $cn + c$ came about.
Thank you.

Hint:
$$\underbrace{c+c+c+\dots+c}_n=cn$$
Likewise...
$$c(n+1)=cn+c$$
