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?
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}.
To return to the initial temperature of 81°F, we need to calculate the net change in temperature after it dropped 9°F and then rose 5°F.
Step 1: The temperature dropped 9°F, so we subtract 9 from the initial temperature:
81°F - 9°F = 72°F
Step 2: The temperature then rose 5°F, so we add 5 to the result from step 1:
72°F + 5°F = 77°F
Step 3: To return to the initial temperature of 81°F, we need to calculate the difference between 77°F (current temperature) and 81°F (initial temperature):
81°F - 77°F = 4°F
Therefore, the temperature needs to rise 4°F to return to the initial temperature of 81°F.
To find out how much the temperature needs to rise or fall to return to the initial temperature of 81°F, we need to calculate the difference between the final temperature and the initial temperature.
Let's break down the steps:
1. Initial temperature: 81°F
2. The temperature dropped 9°F, so subtract 9 from the initial temperature: 81°F - 9°F = 72°F
3. The temperature then rose 5°F, so add 5 to the previous result: 72°F + 5°F = 77°F
To find out how much the temperature needs to rise or fall to return to the initial temperature of 81°F, subtract the final temperature (77°F) from the initial temperature (81°F):
81°F - 77°F = 4°F
Therefore, the temperature needs to rise by 4 degrees Fahrenheit to return to the initial temperature of 81°F.