The operation described by:
(-71) + (+47) implies combining a negative number (-71) with a positive (+47).
Now the absolute value of the negative number is larger than that of the positive number, therefore your answer will be NEGATIVE:
- 71 + 47 = - 24
When you combine (add) two negative numbers, the answer is NEGATIVE.
- 15 + (- 32) = - 67
Think of this as owing $15 to a friend, and then asking you friend again for $32.
At the end you owe your friend $67.
The fact that you "owe" instead of "own" is what makes the number negative.
There is a difference though with the "multplication", since the product of two negative numbers will render a positive number. You may be getting confused by that rule. It is important to differenciate between these two operations: Addition , and Multiplication when we deal with signed numbers.