Answer:
-subtraction
Step-by-step explanation:
Elevation is the altitude of a place above a reference frame.
To find the difference between the elevation between two or places on a map, we perform a subtraction operation.
The differences in elevation is the subtraction of the two elevation values from one another.
For example if point A on a map is at 60m above sea level and point B is at 100m, the change in elevation is;
Change in elevation = Elevation of B - Elevation of A = 100m - 60m = 40m