Use the supplied $80 adjustment rate. The $200 figure comes from $300,000 / 1,500 and describes the whole sale price per square foot. It is not automatically the contribution of an additional square foot of living area.

For this exercise, 200 x $80 = $16,000. Add it if the comparable is smaller and inferior for the stated size difference; subtract it if the comparable is larger and superior. Assume the question specifies that this is the only relevant difference.

Outside a classroom exercise, the adjustment rate needs market evidence, as Fannie Mae's guidance explains. Neither $80 nor $200 is a universal rate. Continue with the worked adjustment examples to practice the signs.