Adding and Subtracting Fractions

For “like” fractions (fractions with the same denominator), add or subtract the numerators (top numbers) and write the answer over the common denominator (bottom numbers).

-  Adding and Subtracting fractions with the same denominator:


-  Find equivalent fractions with the same denominator before you can add or subtract fractions with different denominators.
-  Adding and Subtracting fractions with different denominators:


Examples:

Example 1.  Find the sum.
Solution: These two fractions are “unlike” fractions. (they have different denominators). Use this formula:
Then:

Example 2.  Find the difference.
Solution: For “unlike” fractions, find equivalent fractions with the same denominator before you can add or subtract fractions with different denominators. Use this formula: