A building has 4 floors of offices above ground and 5 floors of storage below ground. A worker goes up to the third floor to get some file folders and takes them down to a storage room on the fourth underground level to have the files stored. Part A: How might a number line help you solve this problem? Part B: Should 0 be on your number line? Explain Part C: Sketch a number line. Graph each integer for the 3rd floor, storage room, and main lobby and label the points. Part D: How many floors does she have to go to get back to the main lobby on the first floor?