Answer:
If the temperature cooled by 4° on the first day of the year, and then heated up 7° on the second day, the net change in temperature would be a 3° increase. This means that the temperature increased by a total of 3° over the two days.
Explanation:
On the first day of the year, the temperature starts at a certain degree (let's call it X).
On the same day, the temperature cools by 4°. This means that the temperature becomes X - 4°.
On the second day of the year, the temperature starts at X - 4° (the temperature from the previous day).
On the second day, the temperature heats up by 7°. This means that the temperature becomes (X - 4°) + 7° = X + 3°.
The net change in temperature over the two days is X + 3° - X = 3°.
I hope this helps to clarify the example! Let me know if you have any further questions.