SOLUTION: Evaluate the sum: 1-2+3-4+5-6+7-8+9-10+…-998+999-1000

Algebra ->  Sequences-and-series -> SOLUTION: Evaluate the sum: 1-2+3-4+5-6+7-8+9-10+…-998+999-1000      Log On


   

Question 252456: Evaluate the sum: 1-2+3-4+5-6+7-8+9-10+…-998+999-1000
Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
Evaluate the sum: 1-2+3-4+5-6+7-8+9-10+…-998+999-1000
Notice that each pair of number adds to -1.
There are 500 such pairs, so,
500*(-1) = -500.