Year 3 - Maths
Identify knowns and unknowns in addition 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 addition equations.
Key Notes
- If the sum is missing, you add the addends.
- If an addend is missing, subtract the other addend from the sum to calculate the missing value.
- When the numbers are close together, add on to find the difference.
Vocabulary To Learn
- Addend: An addend is a number added to another.
- Sum: The sum is the the total when numbers are added together.
- Difference: The difference is the result after subtracting one number from another.
Common Mistakes To Avoid
- Pupils may confuse the parts and the whole in an equation, especially when there is a missing number.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
If the sum is missing, you add the addends. If an addend is missing, subtract the other addend from the sum to calculate the missing value.
2. Use this key word in a maths sentence and explain it clearly. 'Addend'
An addend is a number added to another. 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 confuse the parts and the whole in an equation, especially when there is a missing number. Correction: Bar models are helpful for representing and understanding the parts and the whole. Ensure that pupils understand that minuend and sum both represent a whole. Allow lots of opportunities for pupils to sketch bar models.
More Lessons In This Unit
- Develop understanding of the relationship between addition and subtraction Study Guide
- Identify knowns and unknowns in subtraction 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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