Compute (-50) + (-48) + (-46) + .... + 54 + 56.
So from -50 to positive 50 we have the numbers cancelled out.
-50 + 50 = 0, -48 + 48 =0.
52 + 54 + 56 = 162.
That is our answer.
If you don't understand anything feel free to ask!
+1005 
