Answer:
Zero
Step-by-step explanation:
Because integers are equal in magnitude but opposite in sign, therefore they will cancel out each other leaving zero as answer.
[tex] - 20 - 19 - 18 - 17 - 16 - 15.. - 1 + 0 + \\ 1 ..... + 15 + 16 + 17 + 18 + 19 + 20 \\ = 0[/tex]
