Year 5 - Maths
Explain how to find all the factors of a number systematically
Understand and use the concept of factorisation (square and prime numbers)
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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 understand and use the concept of factorisation, explaining what a factor is and how to use arrays and multiplication/division facts to find them. They will identify prime numbers, square numbers and composite numbers.
Lesson Summary
You will learn to explain how to find all the factors of a number systematically.
Key Notes
- All numbers have themselves and 1 as factors.
- Listing factors in order helps identify all the factors for a given number.
Vocabulary To Learn
- Factor: Factors are whole numbers which exactly divide another whole number.
- Systematic: Being systematic, means working in a set way, often according to a fixed plan.
Common Mistakes To Avoid
- Pupils do not know when to stop looking for more factors.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
All numbers have themselves and 1 as factors. Listing factors in order helps identify all the factors for a given number.
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 do not know when to stop looking for more factors. Correction: Build up finding factors of numbers systematically by arranging into rows and columns, starting with 1 row. Encourage pupils to generalise that when the number of rows becomes larger than the number of columns, you can stop looking for factors.
More Lessons In This Unit
- Explain how to identify a prime factor of a number Study Guide
- Explain how to identify a prime number or a composite number Study Guide
- Explain what a factor is and use arrays and multiplication and division facts to find them Study Guide
- Use a complete list of factors to explain when a number is a square number Study Guide
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