Year 3 - Maths
Identify knowns and unknowns in subtraction equations
Understand additive relationships and apply them to rearrange equations
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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 accurately and efficiently solve multi-step addition and subtraction problems. They will understand and explain how both addition and subtraction equations can be used to describe the same additive relationship.
Lesson Summary
You will learn to identify knowns and unknowns in subtraction equations.
Key Notes
- Equations can be represented using part-part-whole or bar models.
- If the minuend is missing, you add the subtrahend and difference.
- To find a missing part in a subtraction equation, subtract the other part from the whole.
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.
Common Mistakes To Avoid
- Pupils may rely on the same strategies to solve all problems and may find it hard to remember when to add to find the missing part and when to subtract.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Equations can be represented using part-part-whole or bar models. If the minuend is missing, you add the subtrahend and difference.
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 may rely on the same strategies to solve all problems and may find it hard to remember when to add to find the missing part and when to subtract. Correction: Emphasise the use of bar models, especially for pupils who are struggling. This will help them identify whether a part is missing or if the whole is missing, and whether they should add the parts or subtract a part from the whole to get the answer.
More Lessons In This Unit
- Develop understanding of the relationship between addition and subtraction Study Guide
- Identify knowns and unknowns in addition equations Study Guide
- Solve multi-step addition and subtraction problems efficiently Study Guide
- Solve one and two-step problems in different contexts Study Guide
- Solve problems using bar charts, pictograms and tables Study Guide
- Understand why the order of addition and subtraction steps can be chosen Study Guide
- Use the additive relationship to rearrange addition equations Study Guide
- Use the additive relationship to rearrange and solve equations Study Guide
- Use the additive relationship to rearrange subtraction equations Study Guide
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