(a) Sea level is 0 , therefore the elevation of city (A) is -96 , and the elevation of city (C) is -24 For this part we do not need the elevation of city (A). The elevation of city (D) is 1/4 of city (C). The key word is OF! Of means to multiply. Therefore we have the expression 24 · 1/4 = -6. As for explaining why it's negative we go back to how a negative times a positive is a negative.