The answer to the sunset question is 16 F.
Work Example:
With the number -2, you can order the work simple like these examples over here.
18 + (-2) = 16.
The problem is usually written like this, and here is a little trick. When a positive number is added to a negative number, instead of adding itself, it subtracts the positive form of the negative number with 18, which is our positive number.
18 - 2 = 16.
If you place the -2 as the second number in the equation, the negative works nicely and looks like a minus sign. Or, you can do it in a different way.