Adding
When you add a positive and negative number, you need to look at the "size" or "magnitude" of the number.
-32 has a magnitude of 32 and is negative.
The answer will be positive, if the positive number has a bigger magnitude.
The answer will be negative, if the negative number has a bigger magnitude.
Subtracting
Remember that subtracting a negative number is the same as adding its positive.
When you subtract a smaller number from a larger number, the answer is positive.
When you subtract a larger number from a smaller number, the answer is negative.
Examples
6 - 7 is negative
7 - 6 is positive
-6 - 7 is negative
-6 + 7 is positive
-6 - -7 = -6 + 7 which is positive