Year 6 - Maths
Add and subtract non-related fractions with different denominators
Addition and subtraction of fractions
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit pupils will explain how to write a fraction in its simplest form when solving addition and subtraction problems.
Lesson Summary
You will learn to add and subtract non-related fractions with different denominators.
Key Notes
- Common denominators for non-related fractions can be found using common multiples of the denominators.
- Fractions need to have the same denominator if we are to add and subtract them.
- In equivalent fractions, the numerators and denominators have been scaled up or down by the same factor.
Vocabulary To Learn
- Common denominator: When two or more fractions share the same denominator, you can say they have a common denominator.
- Related fractions: Related fractions are when the denominator of one fraction is a multiple of the denominator of the other fraction.
- Non-related fractions: Non-related fractions are when the denominator of one fraction is not a multiple of the denominator of the other fraction.
- Common multiple: A multiple that is common between two or more numbers is known as a common multiple.
Common Mistakes To Avoid
- When adding or subtracting fractions with different denominators, you just add or subtract the denominators from each other.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Common denominators for non-related fractions can be found using common multiples of the denominators. Fractions need to have the same denominator if we are to add and subtract them.
2. Use this key word in a maths sentence and explain it clearly. 'Common denominator'
When two or more fractions share the same denominator, you can say they have a common denominator. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: When adding or subtracting fractions with different denominators, you just add or subtract the denominators from each other. Correction: Encourage the children to use prior generalisations such as when the numerators are the same, the fraction with the largest denominator is the smallest, to help them reason about the above misconception.
More Lessons In This Unit
- Explain how to add related unit fractions with a representation or image Study Guide
- Explain how to add related unit fractions without a representation or image Study Guide
- Explain how to subtract related unit fractions Study Guide
- Explain how to write a fraction in its simplest form Study Guide
- Explain with and without an image how to add and subtract related non-unit fractions Study Guide
- Explain with and without images how to add and subtract related non-unit fractions bridging a whole Study Guide
- Reason about how to write a fraction in its simplest form Study Guide
- Use knowledge of adding and subtracting related unit fractions to solve problems Study Guide
- Use knowledge of fractions in their simplest form when solving addition and subtraction problems Study Guide
Browse all guides in the Year 6 Maths guide library.