Answer:
Expression: 18 - 12 + 7. In 3 days, the temperature will be 13 degrees.
Explanation:
The temperature is 18 degrees.
It will decrease 12 degrees after one day. So, it is 18 - 12.
Then it will increase by 7 degrees after another day. So, it is 18 - 12 + 7.
18 - 12 = 6. 6 + 7 = 13.
So, the expression is 18 - 12 + 7 and the answer is 13 degrees (i think)