Which situation results in a change that could be modeled by a negative number?
a change in elevation from 492 feet to 783 feet
a change in elevation from –12 feet to 123 feet
a change in elevation from sea level to 87 feet
a change in elevation from 632 feet to 312 feet

The answer would be a change in elevation from 632 feet to 312 feet. This is because it is the only change where the elevation is decreasing. All of the other changes are increasing from a lower elevation to a higher one. Also what might help you to understand is all of the others add a positive number. For instance, sea level (0 feet) has to add 87 feet to get to 87 feet elevation. But, for the 632 feet it has to add -320 feet to get to 312 feet. Hope this helped!