Descending: subtraction
Rises: Addition
The diver descends 100ft: Position -100 (the 0 is the sea level)
Then rises 28: Add 28 to the previous position: Position -72
[tex]-100+28=-72[/tex]...before descending another 33: Subtract 33 to the previous position:
[tex]-72-33=-105[/tex]Then, the final position is -105ft (105 ft under the sea level)
