Ineed don't understand this problem.
trina and jessie went on vacation. trina went scuba diving and reached an elevation of -85.5 meters, which is below sea level. jessie went hang gliding and reached 87.9 meters which is above sea level.
who is closer to the surface of the ocean? explain

We need to find the absolute value of these numbers to see which one is closer to the surface of the ocean. The surface of the ocean is at 0.

Trina : | - 85.5 | = 85.5 meters from 0
Jessie : | 87.9 | = 87.9 meters from 0

so Trina is closer to 0 then Jessie is. <==
The reason we took the absolute value of these numbers, is because that is what the absolute value does...it tells us how many spaces away from 0 it is.