Free Grade 3 Prime Numbers Lesson Plans
Free Grade 3 lesson plans for Prime Numbers: 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
Higher
30 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- RememberIdentify prime numbers
Identify prime numbers accurately in a familiar context.
Assessed by: Exit ticket of four short items
- UnderstandExplain prime numbers
Explain prime numbers accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate prime numbers
Calculate prime numbers accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare prime numbers
Compare prime numbers 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 Prime Numbers 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 40.[1]
- 2.List all the factors of 18.[1]
- 3.List all the factors of 36.[1]
- 4.List all the factors of 12.[1]
- 5.Find the highest common factor (HCF) of 32 and 40.[2]
- 6.Find the highest common factor (HCF) of 49 and 49.[2]
- 7.Find the highest common factor (HCF) of 63 and 36.[2]
- 8.Find the highest common factor (HCF) of 36 and 45.[2]
- 9.Find the lowest common multiple (LCM) of 15 and 21.[3]
- 10.Find the lowest common multiple (LCM) of 8 and 20.[3]
- 11.Find the lowest common multiple (LCM) of 36 and 30.[3]
- 12.Find the lowest common multiple (LCM) of 27 and 54.[3]
Show answers and working
1. 1, 2, 4, 5, 8, 10, 20, 40
Find factor pairs that multiply to 40. 1 × 40 2 × 20 4 × 10 5 × 8
2. 1, 2, 3, 6, 9, 18
Find factor pairs that multiply to 18. 1 × 18 2 × 9 3 × 6
3. 1, 2, 3, 4, 6, 9, 12, 18, 36
Find factor pairs that multiply to 36. 1 × 36 2 × 18 3 × 12 4 × 9 6 × 6
4. 1, 2, 3, 4, 6, 12
Find factor pairs that multiply to 12. 1 × 12 2 × 6 3 × 4
5. 8
List factors of 32 and 40. The largest factor they share is 8.
6. 49
List factors of 49 and 49. The largest factor they share is 49.
7. 9
List factors of 63 and 36. The largest factor they share is 9.
8. 9
List factors of 36 and 45. The largest factor they share is 9.
9. 105
HCF(15, 21) = 3. LCM = 15 × 21 ÷ 3 = 105.
10. 40
HCF(8, 20) = 4. LCM = 8 × 20 ÷ 4 = 40.
11. 180
HCF(36, 30) = 6. LCM = 36 × 30 ÷ 6 = 180.
12. 54
HCF(27, 54) = 27. LCM = 27 × 54 ÷ 27 = 54.
Worked examples
List all the factors of 28.
- Find factor pairs that multiply to 28.
- 1 × 28
- 2 × 14
- 4 × 7
- Answer: 1, 2, 4, 7, 14, 28
Find the highest common factor (HCF) of 18 and 24.
- List factors of 18 and 24.
- The largest factor they share is 6.
- Answer: 6
Find the lowest common multiple (LCM) of 24 and 30.
- HCF(24, 30) = 6.
- LCM = 24 × 30 ÷ 6 = 120.
- Answer: 120
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 Prime Numbers
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Learn — Meet the idea.
Practice — Build fluency.
Revise — Keep it in memory.
Assess — Prove mastery.
Apply — Use it in context.
Teach — Deliver it to a class.
Frequently asked
- Is this Grade 3 Prime Numbers lesson plan really free?
- Yes. Every lesson plans 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 Multiples, Factors, Proportion. Each one has its own free lesson, worksheet and quiz.
- How is the lesson plan 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 Prime Numbers?
- Move on to Prime Factorisation, HCF, LCM, Whole Numbers, which build directly on this idea.
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