Alexis took an elevator one floor down from the lobby of her office building to the parking garage. Then she took the elevator back up 5 floors to her office. She described her movement with this expression: 1+5 What was Alexis’ error? She should have used –1 for moving below the lobby. She should have used –5 for moving up 5 floors. She should have used –1 for her movement down and –5 for her movement up. She should have started at zero and then added 6.

Answer:Her mistake was that she should have used –1 for moving below the lobby.Step-by-step explanation:Lets denote the lobby as Floor zero (0)- if you go up, you add a positive value to this quantity.- if you go down, you add a negative value to this quantity.Lets assume that moving through each floor is equivalent to advancing one unit* She first took an elevator one floor down (-1)Then she took the elevator back up 5 floors to her office(+5)Her movement is described by the expression(-1) + (5)Her mistake was that she should have used –1 for moving below the lobby.