Free Grade 3 Working with LCM Lessons
Free Grade 3 lessons for Working with LCM: 12 real questions with a full answer key and worked solutions. Factors divide a number exactly; multiples are in its times table. The HCF is the biggest shared factor, the LCM the smallest shared multiple.
Free
Foundation
30 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- RememberIdentify working with lcm
Identify working with lcm accurately in a familiar context.
Assessed by: Exit ticket of four short items
- UnderstandExplain working with lcm
Explain working with lcm accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate working with lcm
Calculate working with lcm accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare working with lcm
Compare working with lcm accurately in a familiar context.
Assessed by: Exit ticket of four short items
Prerequisites
Close these gaps first — each has its own free lesson, worksheet and quiz.
How Working with LCM works
Factors divide a number exactly; multiples are in its times table. The HCF is the biggest shared factor, the LCM the smallest shared multiple.
12 practice questions
Easy to hard, 24 marks in total. Try them first, then open the answers.
- 1.List all the factors of 24.[1]
- 2.List all the factors of 28.[1]
- 3.List all the factors of 12.[1]
- 4.List all the factors of 20.[1]
- 5.Find the highest common factor (HCF) of 24 and 36.[2]
- 6.Find the highest common factor (HCF) of 35 and 28.[2]
- 7.Find the highest common factor (HCF) of 20 and 30.[2]
- 8.Find the highest common factor (HCF) of 16 and 56.[2]
- 9.Find the lowest common multiple (LCM) of 21 and 9.[3]
- 10.Find the highest common factor (HCF) of 42 and 42.[3]
- 11.Find the lowest common multiple (LCM) of 24 and 20.[3]
- 12.Find the lowest common multiple (LCM) of 35 and 20.[3]
Show answers and working
1. 1, 2, 3, 4, 6, 8, 12, 24
Find factor pairs that multiply to 24. 1 × 24 2 × 12 3 × 8 4 × 6
2. 1, 2, 4, 7, 14, 28
Find factor pairs that multiply to 28. 1 × 28 2 × 14 4 × 7
3. 1, 2, 3, 4, 6, 12
Find factor pairs that multiply to 12. 1 × 12 2 × 6 3 × 4
4. 1, 2, 4, 5, 10, 20
Find factor pairs that multiply to 20. 1 × 20 2 × 10 4 × 5
5. 12
List factors of 24 and 36. The largest factor they share is 12.
6. 7
List factors of 35 and 28. The largest factor they share is 7.
7. 10
List factors of 20 and 30. The largest factor they share is 10.
8. 8
List factors of 16 and 56. The largest factor they share is 8.
9. 63
HCF(21, 9) = 3. LCM = 21 × 9 ÷ 3 = 63.
10. 42
List factors of 42 and 42. The largest factor they share is 42.
11. 120
HCF(24, 20) = 4. LCM = 24 × 20 ÷ 4 = 120.
12. 140
HCF(35, 20) = 5. LCM = 35 × 20 ÷ 5 = 140.
Worked examples
List all the factors of 36.
- Find factor pairs that multiply to 36.
- 1 × 36
- 2 × 18
- 3 × 12
- 4 × 9
- 6 × 6
- Answer: 1, 2, 3, 4, 6, 9, 12, 18, 36
Find the highest common factor (HCF) of 24 and 42.
- List factors of 24 and 42.
- The largest factor they share is 6.
- Answer: 6
Find the lowest common multiple (LCM) of 54 and 18.
- HCF(54, 18) = 18.
- LCM = 54 × 18 ÷ 18 = 54.
- Answer: 54
Interactive practice
Free, no account required — answer on screen or print it.
Common mistakes
What learners typically get wrong, and how to fix it.
Mixes up factors and multiples.
Correction: Factors are Few (they fit inside), multiples are Many (they go on forever).
Misses factor pairs.
Correction: Work through 1, 2, 3… in order until the pairs meet.
Teacher tips
- · Use factor rainbows to show pairs.
Parent tips
- · Ask how many ways 24 sweets can be put into equal bags.
Real-life applications
- · Arranging chairs in equal rows, syncing bus timetables (LCM).
Assessment objectives
How mastery is evidenced, and which standards it maps to.
Every free resource for Working with LCM
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Learn — Meet the idea.
Practice — Build fluency.
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Teach — Deliver it to a class.
Frequently asked
- Is this Grade 3 Working with LCM lesson really free?
- Yes. Every lessons on FreeMathWorksheet is free to use, print and share — no account, no paywall and no watermark.
- What should a learner already know before this?
- Start with Introducing LCM, HCF. Each one has its own free lesson, worksheet and quiz.
- How is the lesson sequenced?
- Recognition first, then understanding, application, reasoning and finally mastery — the same ladder used across every free resource on the platform.
- What comes next after Working with LCM?
- Move on to LCM in Context, Factors, Multiples, Prime Numbers, which build directly on this idea.
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