Adding two positive numbers gives a positive answer.
Adding two negative numbers gives a negative answer.
Examples
5 + 11 = 16
-5 + -11 = -16
Adding a negative number is the same as subtracting the positive.
The answer may be positive or negative depending on the size of the numbers.
Examples
5 + -11 = 5 - 11 = -6
5 + -3 = 5 - 3 = 2