A submarine descends 45 1/2 feet from the ocean surface, clinbs 39 ft, and then descends an additional 18 3/4 ft. What must the submarine now do to reach the ocean surface?

The answer is fill its tanks with air so it floats to the top, but I will solve for the distance since I am nice

so we do

decent means negative

cimb=positive

add

decends 45 and 1/2

-45 and 1/2

climbs 39

+39

decedns 18 and 3/4

-18 and 3/4

add

-45 and 1/2+39-18 and 3/4

add

convert 1/2 to 2/4

gropu negatives

-45 and 2/4-18 and 3/4+39

add

-63 and 5/4+39

-64 and 1/4+39

-25 and 1/4

that is how far dow the submarine is

so the submarine needs to gu 25 and 1/4 ft up to reach the csurface