Year 6 - Maths
Explain how adjusting the subtrahend affects the difference: reduction structure
Use equivalence and compensation to simplify and solve subtraction problems
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Study Guides
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 increasing or decreasing the minuend affects the difference and solve subtraction calculations mentally by using known facts explaining how adjusting the minuend can make mental calculation easier.
Lesson Summary
You will learn to explain how adjusting the subtrahend affects the difference in a reduction structure.
Key Notes
- The more you subtract the less you are left with.
- The less you subtract the more you are left with.
- A number line can be used to represent the change in the subtrahend.
Vocabulary To Learn
- Minuend: The minuend is the number being subtracted from.
- Subtrahend: A subtrahend is a number subtracted from another.
- Difference: The difference is the result after subtracting one number from another.
- Adjust: When you adjust you make a change to a number. This is done to make a calculation easier to solve mentally.
Common Mistakes To Avoid
- Pupils might think that if the subtrahend increases or decreases then so too does the difference. They might find it initially difficult to understand the idea of the inverse in the context.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
The more you subtract the less you are left with. The less you subtract the more you are left with.
2. Use this key word in a maths sentence and explain it clearly. 'Minuend'
The minuend is the number being subtracted from. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils might think that if the subtrahend increases or decreases then so too does the difference. They might find it initially difficult to understand the idea of the inverse in the context. Correction: Give lots of practical examples of this such as emptying out bottles or eating sweets demonstrating an increase in the subtrahend and its effect on the difference.
More Lessons In This Unit
- Calculate the difference using knowledge of an adjusted subtrahend: difference structure Study Guide
- Explain and represent constant difference for subtraction Study Guide
- Explain how adjusting the minuend can make mental calculation easier Study Guide
- Explain how adjusting the subtrahend affects the difference: partitioning Study Guide
- Explain how constant difference can make written calculations more efficient Study Guide
- Explain how increasing or decreasing the minuend affects the difference Study Guide
- Solve subtraction calculations mentally by using known facts Study Guide
- Use constant difference to balance equations and find unknowns Study Guide
- Use equivalence and compensation strategies to solve subtraction problems in a range of contexts Study Guide
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