suppose you deliver mail in an office building. You leave the mailroom and enter the elevator next door. you go up 4 floors, down 7, and up nine to the top floor. Then,you go down 6, up 2 and down 8 to the lobby on the first floor. What floor is the mailroom on?

Answer 1

from mailroom at floor x :
x + 4 - 7 + 9 - 6 + 2 - 8 = 1
x = ....