adding integers with different signs

Question

adding integers with different signs

 

Answer 1

The way you add two integers if each can have either sign is as follows.

 

Case 1: At least one of them is 0.

 

0 + n = n + 0 = n.

 

Case 2: Same signs.

 

Add their absolute values and keep the sign.

 

For example, say you want to add -5 and -7. Start with with 5+7 = 12. Since both are negative, the answer will also be negative so you get a sum of -12.

 

Case 3: Opposite signs.

 

Take the difference between absolute values first. Then take the sign of the integer with larger absolute value.

 

For example, say we want to add int 5 and -7. Start with 7 - 5 = 2. Since -7 has larger absolute value, the answer will be negative, and so must be -2.

Answer 2

Always find the difference of their absolute values. Then assign the sign, positive or negative, based on the higher absolute value.

 

For example,

13+ (-14)

1. the absolute values are, |13|=13 and |-14|=14
2. 14-13=1
3. since, |-14|>|13|, because 14>13, the sign of your answer will be negative,
4. 13+ (-14)=-1