Year 4 - Maths
Subtract a mixed number from a mixed number
Efficient strategies for adding and subtracting mixed numbers (crossing a whole)
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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 add mixed numbers. They will subtract a proper fraction from a mixed number and subtract a mixed number from a mixed number explaining which strategy is most efficient.
Lesson Summary
You will learn to subtract a mixed number from a mixed number explaining which strategy is most efficient.
Key Notes
- To subtract mixed numbers, we need to use our fraction-sense to determine the most appropriate strategy to use.
- Mixed numbers can be subtracted by counting back using a number line or by converting them to improper fractions.
- If mixed numbers are close, it is more efficient to 'find the difference' by counting forwards from part to whole.
Vocabulary To Learn
- Mixed number: A mixed number is a whole number and a fraction combined.
- Improper fraction: An improper fraction is a fraction where the numerator is greater than or equal to the denominator.
Common Mistakes To Avoid
- Children may believe that a smaller mixed number cannot be subtracted from a greater one if its fractional part is greater. E.g. five and three-quarters cannot be subtracted from six and one-quarter.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
To subtract mixed numbers, we need to use our fraction-sense to determine the most appropriate strategy to use. Mixed numbers can be subtracted by counting back using a number line or by converting them to improper fractions.
2. Use this key word in a maths sentence and explain it clearly. 'Mixed number'
A mixed number is a whole number and a fraction combined. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Children may believe that a smaller mixed number cannot be subtracted from a greater one if its fractional part is greater. E.g. five and three-quarters cannot be subtracted from six and one-quarter. Correction: If the mixed numbers are close to each other, try to 'find the difference' by counting forwards on a number line from the part to the whole.
More Lessons In This Unit
Browse all guides in the Year 4 Maths guide library.