Simplify a fraction
6/8 simplifies to 3/4 because both parts divide by 2.
Divide the numerator and denominator by the same number.
Year 6
Use common factors to simplify fractions and use common multiples to express fractions in the same denomination
Simplify fractions and rewrite fractions using a common denominator.
Lesson overview
Number - fractions, decimals and percentages
A fraction can be simplified by dividing the numerator and denominator by the same common factor. Fractions can be rewritten with a common denominator by finding a shared multiple of the denominators.
Use a common denominator
1/3 and 1/6 can both be written in sixths.
| Original | Equivalent |
|---|---|
| 1/3 | 2/6 |
| 1/6 | 1/6 |
Matching denominators helps comparison and calculation.
Worked example
Simplify 12/18.
| Common factor | Result |
|---|---|
| divide by 6 | 2/3 |
- Find a common factor of 12 and 18.
- Both numbers divide by 6.
- 12/18 becomes 2/3.
- So the simplified fraction is 2/3.
Try it
Look for a common factor or common multiple before you answer.
Question 1
6/8 simplifies to:
Question 2
A common denominator for 1/4 and 1/6 is:
Question 3
12/18 simplifies to:
Question 4
Which pair already has the same denominator?
Question 5
Which fraction is already in simplest form?
Common mistakes
Watch for these when working through the lesson.
- Dividing only the numerator or only the denominator.
- Using different divisors for the top and bottom.
- Choosing a denominator that is not common to both fractions.
Related topics
These ideas fit closely with this lesson.
- Compare and order fractions, including fractions greater than 1.
- Add and subtract fractions with different denominators.