Fraction Rules from Class

Adding or Subtracting Fractions is "Painless", When You Know the Rules!


Adding or Subtracting fractions is a pretty straightforward operation, if you follow the rules. But the key is to make sure the denominators are the same. That way, our point of reference is the same and we can now work the problem.

Here is the Rule for adding or subtracting fractions:

1)If needed, we have to build each fraction so that the denominators are the same.
2)Then, we add the numerators.
3)The denominator of your answer will be the same denominator of the built-up fractions. 4) As always we have to reduce or simplify the answer, if required

Note: We Do Not Add or Subtract denominators!

To add or subtract fractions with a common denominator, you simply omit Step#1.

When adding fractions with different denominators, we do all the steps

1/2 + 1/3 = 3/6 + 2/6 = 
(3 + 2)/6 = 5/6

Caution!!!
If you are subtracting fractions and need to borrow, follow these steps:
Subtracting Fractions with Borrowing (renaming)

1. Make sure you have a common denominator.
2. If the number you are subtracting by is smaller, borrow one whole from the whole number.

3. Add the whole to the fraction by making it an improper fraction.

4. Subtract the numerators and remember to also subtract the whole numbers if there are any left.
Adding/ Subtracting Fractions with Different Denominators

How to Add Fractions with different denominators

1. Find the Least Common Denominator (LCD) of the fraction

2. Rename the fractions to have the LCD

3. Add or Subtract the numerators of the fractions

4. Simplify the Fraction