A submarine starts at 215 sea level. It’s ascends 89 feet and then descends 164 feet. Represent its current depth with respect to sea level as an integer.

Answer 1

I have to make an assumption here in that the sub begins at 215 feet below sea level.

If it ascends 89 feet then it is now 215-89=126 feet below sea level.

When it next descends another 164 feet, the resulting position is 126+164 = 290 feet below sea level.

Looking at this from the perspective of integers we have:

-215 + 89 - 164 = -290

Remember, integers are positive or negative, and include 0. Fractions and decimals are not integers.