The temperature initially dropped 9°F and then rose 5°F, so the net change in temperature is -9°F + 5°F = -4°F.
To return to the initial temperature of 81°F, the temperature needs to rise 4°F. Answer: \boxed{4}.
On a given morning the temperature was 81°F. The temperature dropped 9°F and then rose 5°F. How much does the temperature need to rise or fall to return to the initial temperature of 81°F?
1 answer