A plane is flying at the height of 5000m above the sea level.At aparticul point ,it is exactly above a submarin floatig 1200m below the sea level. What is the vertical distance between them? why do we subtract in this Q

the vertical distance is 7200 m as the plane's height is 5000m above sea level and the submarine is 1200 m below sea level so

the vertical distance is [5000+1200]m=7200m