Year 1 - Maths
Find the missing part of a subtraction story
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 find the missing part of a subtraction story when the other two parts are known.
Key Notes
- When an amount is changed by subtracting, to undo the change, we must add the same amount back on.
- The amount that has been subtracted can be found using the known parts.
Vocabulary To Learn
- Add: To find the total, or sum, by combining two or more parts, or to increase an amount by adding another.
- Subtract: To partition one part from another, or to decrease an amount by taking an amount away.
- Then: After something in time.
Common Mistakes To Avoid
- On recognising the subtraction symbol, children may believe that the two parts known must be subtracted from each other, regardless of which part of the equation is missing.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
When an amount is changed by subtracting, to undo the change, we must add the same amount back on. The amount that has been subtracted can be found using the known parts.
2. Use this key word in a maths sentence and explain it clearly. 'Add'
To find the total, or sum, by combining two or more parts, or to increase an amount by adding another. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: On recognising the subtraction symbol, children may believe that the two parts known must be subtracted from each other, regardless of which part of the equation is missing. Correction: Use practical equipment on 'First, then, now' boards and on part-part-whole models to demonstrate additive relationships and encourage them to use their number sense to think about and predict plausible answers.
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 an addition story Study Guide
- Furthering understanding of subtraction as decreasing an amount 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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