MA02-02 Maths Watch
Highest common factor (HCF)
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In this lesson
In this video you'll learn about highest common factor (HCF) for GCSE Maths, with worked examples and the mistakes examiners report. By the end you'll be able to find the highest common factor of two or more numbers by listing factors or using prime factorisation, correctly extracting the HCF from the shared factors and showing enough working to earn full marks.
What it covers
- 1:04 Highest common factor (HCF): definition + warning
- 2:53 Worked example - 90 and 126
- 5:08 Exam technique
- 6:15 Worked example - caterer
- 8:11 Your turn, properly
- 9:51 What's next
Key words
For: OCR GCSE J560, AQA GCSE 8300, Edexcel GCSE 1MA1, Edexcel IGCSE 4MA1, Eduqas GCSE C300, Cambridge IGCSE 0580
On the specification
| Board | Spec | Statement |
|---|---|---|
| OCR GCSE J560 | 1.02a | Understand and use the terms odd, even, prime, factor (divisor), multiple, common factor (divisor), common multiple, square, cube, root. Understand and use place value. |
| OCR GCSE J560 | 1.02b | Identify prime numbers less than 20. Express a whole number as a product of its prime factors. Understand that each number can be expressed as a product of prime factors in only one way. |
| OCR GCSE J560 | 1.02c | Find the HCF and LCM of two whole numbers by listing. |
| AQA GCSE 8300 | N4 | Use the concepts and vocabulary of prime numbers, factors (divisors), multiples, common factors, common multiples, highest common factor, lowest common multiple, prime factorisation, including using product notation and the unique factorisation theorem |
| Edexcel GCSE 1MA1 | N4 | Use the concepts and vocabulary of prime numbers, factors (divisors), multiples, common factors, common multiples, highest common factor, lowest common multiple, prime factorisation, including using product notation and the unique factorisation theorem |
| Edexcel IGCSE 4MA1 | F1.1H | Identify prime factors, common factors and common multiples |
| Edexcel IGCSE 4MA1 | F1.4E | Find highest common factors (HCF) and lowest common multiples (LCM) |
| Eduqas GCSE C300 | FN4 | Use the concepts and vocabulary of prime numbers, factors (divisors), multiples, common factors, common multiples, highest common factor, lowest common multiple, prime factorisation, including using product notation and the unique factorisation theorem |
| Eduqas GCSE C300 | HN4 | Use the concepts and vocabulary of prime numbers, factors (divisors), multiples, common factors, common multiples, highest common factor, lowest common multiple, prime factorisation, including using product notation and the unique factorisation theorem |
| Cambridge IGCSE 0580 | C1.1 | Types of number |
| Cambridge IGCSE 0580 | E1.1 | Types of number |
For teachers
This GCSE Maths lesson teaches highest common factor (HCF). By the end, students should be able to find the highest common factor of two or more numbers by listing factors or using prime factorisation, correctly extracting the HCF from the shared factors and showing enough working to earn full marks. It works through two worked examples and the mistakes examiners report.