Hi Guest!

All you have to do is subtract 180-80=? because the submarine is 180 feet BELOW sea level, and then accends (rises) 80 feet, so you are taking how far down they went and subtracting how far they went back up out! I would like you to do thw subtraction problem below, and see if you can get your answer. If you still need help just ask :D :P

 

                                                                            180-80=?

I hope this was helpfull! :D :P

-Grace

-180    represents   180 ft BELOW  sea level

       then it rises +80 feet

to   -180 +80 = -100 ft         (or 100 feet BELOW sea level)