1. Adding & Subtracting Negative Fractions

2. Sign rule + X + + - X -+ - X +  - + X -  -
Example 1:-
Step 1 – The sign in the middle (i.e., operation sign) and the sign of the second number to be made into single sign based on sign rule below
Sign rule
+ X + +
- X -+
- X +  -
+ X -  -
Step 2 – To make denominators the same
(Multiply and write)
Step 3 – Now the denominator is the same, add/subtract numerator based on number sign rule below.
Number sign rule
Both signs are same then add and put the same sign
Both signs are different then subtract and put bigger number’s sign
Step 4 - Simplify the fraction

3. Sign rule + X + + - X -+ - X +  - + X -  -
Example 2:-
Step 1 – The sign in the middle (i.e., operation sign) and the sign of the second number to be made into single sign based on sign rule below
Sign rule
+ X + +
- X -+
- X +  -
+ X -  -
Step 2 – To make denominators the same
(Multiply and write)
Step 3 – Now the denominator is the same, add/subtract numerator based on number sign rule below.
Number sign rule
Both signs are same then add and put the same sign
Both signs are different then subtract and put bigger number’s sign
Step 4 - Simplify the fraction

4. Sign rule + X + + - X -+ - X +  - + X -  - LCM Method:
Step 1 – The sign in the middle (i.e., operation sign) and the sign of the second number to be made into single sign based on sign rule below
Sign rule
+ X + +
- X -+
- X +  -
+ X -  -
Step 2 –Find LCM of denominators of both the fractions
LCM (4,6) = 2 x 2 x 3 = 12 (Multiply all the prime factors)
Step 3 – We need to convert both fractions with denominator as 12
Step 4 - Now the denominator is the same, add/subtract numerator based on number sign rule below.
Number sign rule
Both signs are same then add and put the same sign
Both signs are different then subtract and put bigger number’s sign

5. Note
When you use LCM method to add or subtract fraction , you will be multiplying smaller number and you get a smaller fraction.
Also you may not have the need to simplify the resulting fraction.
When adding 3 or more fraction you can use the LCM method to add or subtract all fraction together.

6. Try these