Mastering same denominator fractions for 11+ maths
21 October 2026
Why same denominator fractions matter
Understanding how to add and subtract fractions with the same denominator is a key skill for the 11+ maths exam. It forms the foundation for more complex fraction work.
Step 1: Check the denominators
Before starting, make sure the fractions have the same denominator. For example, 3/8 + 2/8.
Step 2: Add or subtract the numerators
If you are adding, add the top numbers (numerators) together. If you are subtracting, subtract one numerator from the other. The denominator stays the same.
Worked example
3/8 + 2/8
Add the numerators: 3 + 2 = 5
Keep the denominator: 8
The answer is 5/8.
Step 3: Simplify if possible
If the answer can be simplified, write it in its simplest form. In our example, 5/8 is already simplified.
Summary
Adding and subtracting fractions with the same denominator is straightforward. Always check the denominators, work with the numerators, and simplify if needed.
Key insight: When the denominators are the same, you only need to focus on the numerators, making the calculation much easier for your child.
