Year 5 - Maths
Use properties of numbers and the commutative and associative laws to simplify calculations
Use common factors and multiples to solve calculations efficiently
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Study Guides
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 explain how to identify common factors and multiples and use this knowledge of properties of number along with knowledge of the commutative and associative laws to solve problems in a range of contexts.
Lesson Summary
You will learn to use properties of numbers and the commutative and associative laws to simplify calculations.
Key Notes
- By rearranging a calculation it can be made easier to solve mentally
Vocabulary To Learn
- Factor: Factors are whole numbers which exactly divide another whole number.
- Commutative: The commutative law states that you can write the values of a calculation in a different order without changing the calculation; the result is the same. It applies for addition and multiplication.
- Associative: The associative law states that it doesn't matter how you group or pair values (i.e. which we calculate first), the result is still the same. It applies for addition and multiplication.
Common Mistakes To Avoid
- Pupils may struggle to find factors of a number if they do not have automatic recall of their times tables.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
By rearranging a calculation it can be made easier to solve mentally. By rearranging a calculation it can be made easier to solve mentally.
2. Use this key word in a maths sentence and explain it clearly. 'Factor'
Factors are whole numbers which exactly divide another whole number. 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 struggle to find factors of a number if they do not have automatic recall of their times tables. Correction: Provide children with a multiplication grid to help pupils understand the process of the calculations, however ensure additional support is in place for children to build towards automatic recall of times tables.
More Lessons In This Unit
- Explain how to identify a common multiple of two or more numbers Study Guide
- Explain how to identify common factors between two or more numbers Study Guide
- Explain how to use the factor pairs of 100 to solve calculations efficiently Study Guide
- Use knowledge of properties of number to solve problems Study Guide
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