Question

Mount McKinley, the highest mountain in North
America, is 20,320 feet above sea level. Death Valley,
the lowest point in North America, is 280 feet below sea level. Find the difference in height between Mount
McKinley and Death Valley.

Answer 1

Since the deepest point of Death Valley is below sea level, its altitude is negative. So, the difference between the altitudes is

$20320-(-280)$

Subtracting a negative means to add, so we have

$20320-(-280)=20320+280=20600$