How to Add Fractions with the Same Denominator

When two fractions have the same denominator, the pieces are already the same size, so there is no common denominator to find. You simply add the numerators and keep the denominator the same.

Step by step

1. 1
   Check the denominators match
   Both fractions must have the same bottom number. For 2/7 and 3/7, both denominators are 7.
2. 2
   Add the numerators
   Add only the top numbers: 2 + 3 = 5.
3. 3
   Keep the denominator
   The denominator stays the same: the answer is 5/7.
4. 4
   Simplify if needed
   Reduce to lowest terms if possible. 5/7 is already in lowest terms.

Worked example

Add 2/7 + 3/7. The denominators already match, so add the numerators: 2 + 3 = 5. Keep the denominator 7. The answer is 5/7.

Common mistakes to avoid

• Adding the denominators as well (2/7 + 3/7 is not 5/14).
• Forgetting to simplify when the result can be reduced.
• Converting an improper result like 9/7 — remember you can leave it or write it as a mixed number.

Practice this skill

Try it yourself on the Add Fractions Calculator, generate a printable worksheet, or work through it one step at a time in guided practice.