The lowest temperature in the 50 states of usa was in prospect camp, alaska, at -79.8 degrees fahrenheit. in 1913 the temperature at greenland ranch, california, was 213.8 degrees higher than the temperature in prospect camp. what was the temperature at greenland ranch?

You need to add -79.8 and 213.8.

You are adding a positive number, 213.8, and a negative number, -79.8.

First take the absolute value of both numbers.
That means make them both positive.

Use 213.8 and 79.8.
Now subtract the way you always subtracted numbers before you learned about negative numbers. Subtract the smaller number from the larger number.

213.8 - 79.8 =

    213.8
-     79.8

    134.0

213.8 - 79.8 = 134

Now look at the two numbers you subtracted, 213.8 and 79.8. The greater number is 213.8. Before taking the absolute value and getting 213.8, 213.8 was positive, so the answer is positive.

134 degrees