Year 6 - Maths
Solve calculations with missing parts
Use equivalence and compensation to simplify and solve addition calculations
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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 used the concept of same sum to simplify and solve addition problems.
Lesson Summary
You will learn to solve addition calculations with missing parts.
Key Notes
- The change in the sum is equal to the change in the missing addend.
- To calculate the missing addend, the known addend must be subtracted from the sum.
- A bar model can be used to represent a calculation with a missing addend.
Vocabulary To Learn
- Equation: An equation is used to show that one number, calculation or expression is equal to another.
- Unknown: An unknown is a quantity that has a set value but it is represented by a symbol or letter.
- Whole: The whole is all the parts or everything, the total amount.
- Part: A part is a piece or section of the whole.
Common Mistakes To Avoid
- The children might be inclined not to look at previous equations to help them. They might not make use of the adjustments to the whole.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
The change in the sum is equal to the change in the missing addend. To calculate the missing addend, the known addend must be subtracted from the sum.
2. Use this key word in a maths sentence and explain it clearly. 'Equation'
An equation is used to show that one number, calculation or expression is equal 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: The children might be inclined not to look at previous equations to help them. They might not make use of the adjustments to the whole. Correction: Practise some really simple versions. Start with 1 + 2 = 3 and then ask them to adjust 3 by a single-digit number. Write this underneath and then ask them which part has changed and by how much? How do they know?
More Lessons In This Unit
- Explain how adjusting one part affects the sum Study Guide
- Solve addition calculations mentally by using known facts Study Guide
- Solve addition calculations mentally by using known facts in a range of contexts Study Guide
- Use a balanced equation to calculate unknown parts Study Guide
- Use equivalence and compensation strategies to solve addition problems in a range of contexts Study Guide
- Use equivalence and compensation strategies to solve problems Study Guide
- Using balanced equations to calculate redistribution Study Guide
- Using redistribution with addition of decimal fractions Study Guide
- Using redistribution with addition of integers Study Guide
Browse all guides in the Year 6 Maths guide library.