Primes, factors, multiples, HCF and LCM
Prime numbers are the atoms of arithmetic — every other whole number is built by multiplying them together.
Part of your national curriculum
- Number: Use the concepts and vocabulary of prime numbers, factors, multiples, common factors, common multiples, highest common factor and lowest common multiple
Lesson overview
What you'll learn in this lesson
Use the concepts and vocabulary of prime numbers, factors, multiples, common factors, common multiples, highest common factor and lowest common multiple
Key learning points
- • Primes and factors
- • Worked example: HCF
- • Worked example: LCM
This lesson at a glance
- 26 minutes
- 17 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 17
Visual introductionPicture this
Primes, factors, multiples, HCF and LCM
Prime numbers are the atoms of arithmetic — every other whole number is built by multiplying them together.
In a nutshell
Use the concepts and vocabulary of prime numbers, factors, multiples, common factors, common multiples, highest common factor and lowest common multiple
Learning cycle
Part 2 of 17
Learning cycle 1 of 2
Part 1 · Primes and factors
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 17
Learn
Primes and factors
A prime number has exactly two factors: 1 and itself, like 2, 3, 5, 7, 11. Factors of 12 are 1, 2, 3, 4, 6, 12 — numbers that divide it exactly.
Reset break
Part 4 of 17
Pause
That's sitting 1 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 17
Learn
Worked example: HCF
Find the HCF of 18 and 24. Factors of 18: 1, 2, 3, 6, 9, 18. Factors of 24: 1, 2, 3, 4, 6, 8, 12, 24. The highest common factor is 6.
Quick check
Part 6 of 17
Quick check
Part 7 of 17
Reset break
Part 8 of 17
Pause
That's sitting 2 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 17
Learning cycle 2 of 2
Part 2 · Worked example: LCM
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 17
Learn
Worked example: LCM
Find the LCM of 4 and 6. Multiples of 4: 4, 8, 12, 16. Multiples of 6: 6, 12, 18. The lowest common multiple is 12.
Quick check
Part 11 of 17
Reset break
Part 12 of 17
Pause
That's sitting 3 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 13 of 17
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 14 of 17
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
A prime number has exactly two ____: 1 and itself, like 2, 3, 5, 7, 11.
Factors of 12 are 1, 2, 3, 4, 6, 12 — ____ that divide it exactly.
____ of 4: 4, 8, 12, 16.
Challenge round
Part 15 of 17
Game · Recall cards
What is the highest common factor of 36 and 48?
Card 1 of 4
Mastery quiz
Part 16 of 17
Marked quiz
End of lesson quiz: Primes, factors, multiples, HCF and LCM
4 questions, marked with the reasoning shown. No timer.
1. What is the highest common factor of 36 and 48?
2. Which of these is a prime number?
3. What is the HCF of 18 and 24?
4. What is the LCM of 4 and 6?
Lesson round-up
Part 17 of 17
Lesson round-up
Ready when you are
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Luna: 0 out of 3 on the practice checks. Only if you feel up to it — one more?
Ask LunaPart 1 of 17 · Watch & discover
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Use the concepts and vocabulary of prime numbers, factors, multiples, common factors, common multiples, highest common factor and lowest common multiple