On Saturday morning the temperature was 76°F. The temperature dropped 9°F and then rose 13°F. How much does the temperature need to rise or fall to return to the initial temperature of 76°F?
The temperature initially dropped 9°F and then rose 13°F, for a total change of 9°F - 13°F = -4°F.
To return to the initial temperature of 76°F, the temperature needs to rise by 4°F. Answer: \boxed{4}.
To return to the initial temperature of 76°F, we need to find the difference between the current temperature and the initial temperature.
Given that the temperature dropped 9°F and then rose 13°F, the net change in temperature is (9°F - 13°F) = -4°F.
Therefore, the temperature needs to rise by 4°F to return to the initial temperature of 76°F.