What is the summation of (n-3) from n=1 to n=5?

Answer 1

let n=1 -- 1-3 = -2
let n=2 -- 2-3 = -1
let n=3 -- 3-3 = 0
let n=4 -- 4-3 = 1
let n=5 -- 5-3 = 2

then
-2 + (-1) + 0 + 1 + 2 = 0