Answer:
-5°C
Explanation:
if you want to subtract a smaller number from a bigger number you can consider the number line attached below. I have marked 2 and -5 with blue ink.
When you use a number line, firstly see where your first number lies on the number line, in this case 2 is your first number. If you have to subtract a number, you have to move left and if you have to add a number you have to move right on the number line.
As you have to subtract 7 from 2, move 7 spaces to the left counting zero as a number. If you count 7 spaces to the left, it will end at -5.
So your answer is -5°C.
Hope this helps!!