Answer:
If we have an integer number N, the opposite of N will be:
-1*N = -N.
Then, the opposite of 0°C is:
-1*0°C = 0°C.
The number 0 is it's own opposite.
And for 32F, the opposite is:
-1*32F = -32F
So, while the numbers 0°C and 32F physically represent the same thing (the same temperature), mathematically, they behave differently.