Answer:
18 - (-12)
Step-by-step explanation:
Final temp. - Initial temp. = the change in temperature
By -12, we're indicating that is below zero (which is obvious) meaning that it is not in the "normal" scale nor in the imaginary scale of numbers. So, we can operate the following...
18 - (-12) = 30
So the temperature changed by 30 values or the temperature increased by 30 values, because the number is positive.
