Addition  Answer  Example 
Sum of two positive integers  is always a positive number  4 + 5 = 9 
Sum of a positive and negative integer  is either positive or a negative number  3 + 4 = 1 8 + 2 = 8  2 = 6 
Sum of a negative and positive  is either positive number or a negative number  3 + 4 = 1 6 + 2 = 4 
Sum of a two negative integers  is always a negative number  3 + 4 = 7 6 + 2 = 6  2 = 8 
Subtraction  Answer  Example 
Difference of two positive integers  is either positive or a negative number  7  5 = 2 5  7 = 2 
Difference of a positive and negative integer  is always positive number  3  4 = 3 + 4 = 7 6  2 = 8 
Difference of a negative and positive integer  is always negative number  3  +4 = 3  4 = 7 8  +2 = 8  2 = 10 
Difference of a two negative integers  is either positive or a negative number  3  4 = 3 + 4 = 1 6  2 = 6 + 2 = 4 
Method:
 When there are two numbers, one positive and the other negative, subtract and use the sign of the greater number.
 When two numbers are of the same sign, add and use the sign the numbers have,
 When there is a negative sign, before a negative number, it becomes a positive number.
 When there is a positive sign, before a negative number, it remains unchanged.
Example: 45
Since the signs are same, add and use the negative sign.
Answer: 9
Example: 4 (3)
When there is a negative sign before the negative number, it becomes a positive number
4+3
Answer: 7
Example: 7 +(3)
When there is a positive sign before the negative number, it remains unchanged
73
Answer: 4
Negative numbers are used in many ways, including financial statements, altitude measurements, temperature, golf scores and atomic changes.
Directions: Solve the following. Also write 5 examples of each kind.
