Answer:
18.7 °F
Step-by-step explanation:
You want the temperature change between a low of -8.5 °F and a high of 10.2 °F.
The change between the two readings is found by subtracting the smaller from the larger:
10.2 -(-8.5) = 10.2 +8.5 = 18.7
The temperature change is 18.7 °F.