Year 1 - Maths
Furthering understanding of subtraction as decreasing an amount
Additive structures: addition and subtraction
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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 find missing addends in equations. They will partition a whole into 2 parts representing first, then, now stories with subtraction equations. They will learn + and - are inverse operations.
Lesson Summary
You will learn to compare subtraction as decreasing an amount to other addition and subtraction structures.
Key Notes
- Subtraction can be seen as both partitioning and as decreasing an amount.
- Both types of subtraction stories are represented by the same equation.
- In an addition story, the amount at the start of the story is increased.
- In an subtraction story, the amount at the start of the story is decreased.
Vocabulary To Learn
- Subtraction: To partition one part from another (the subtrahend from the difference), or to decrease an amount by taking an amount away.
- Decrease: Make something smaller in size or quantity decrease.
- Addition: To find the total, or sum, by combining two or more parts (addends), or to increase an amount by adding another.
- Increase: To make something larger/greater in size or quantity.
Common Mistakes To Avoid
- After exploring reduction, children may struggle to see partitioning as subtraction because a part is not taken away from the whole.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Subtraction can be seen as both partitioning and as decreasing an amount. Both types of subtraction stories are represented by the same equation.
2. Use this key word in a maths sentence and explain it clearly. 'Subtraction'
To partition one part from another (the subtrahend from the difference), or to decrease an amount by taking an amount away. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: After exploring reduction, children may struggle to see partitioning as subtraction because a part is not taken away from the whole. Correction: Make strong links between equations and different subtraction contexts by focusing on what the subtrahend represents in each case.
More Lessons In This Unit
- Create addition and subtraction stories Study Guide
- Find the missing part in addition and subtraction stories Study Guide
- Find the missing part of a subtraction story Study Guide
- Find the missing part of an addition story Study Guide
- Interpret and represent addition stories Study Guide
- Interpret and represent subtraction stories Study Guide
- Know that addition and subtraction are inverse operations Study Guide
- Represent the inverse relationship between addition and subtraction Study Guide
- Understand subtraction as decreasing an amount Study Guide
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