Free Grade 3 Prime Numbers in Context Lessons
Free Grade 3 lessons for Prime Numbers in Context: 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
Stretch
25 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- UnderstandExplain prime numbers in context
Explain prime numbers in context accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate prime numbers in context
Calculate prime numbers in context accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare prime numbers in context
Compare prime numbers in context accurately in a familiar context.
Assessed by: Exit ticket of four short items
- EvaluateJustify prime numbers in context
Justify prime numbers in context 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 in Context 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 20.[1]
- 2.List all the factors of 24.[1]
- 3.List all the factors of 28.[1]
- 4.List all the factors of 36.[1]
- 5.Find the highest common factor (HCF) of 54 and 18.[2]
- 6.Find the highest common factor (HCF) of 21 and 21.[2]
- 7.Find the highest common factor (HCF) of 9 and 21.[2]
- 8.Find the highest common factor (HCF) of 12 and 30.[2]
- 9.Find the lowest common multiple (LCM) of 20 and 12.[3]
- 10.Find the lowest common multiple (LCM) of 14 and 6.[3]
- 11.Find the lowest common multiple (LCM) of 56 and 48.[3]
- 12.Find the lowest common multiple (LCM) of 9 and 15.[3]
Show answers and working
1. 1, 2, 4, 5, 10, 20
Find factor pairs that multiply to 20. 1 × 20 2 × 10 4 × 5
2. 1, 2, 3, 4, 6, 8, 12, 24
Find factor pairs that multiply to 24. 1 × 24 2 × 12 3 × 8 4 × 6
3. 1, 2, 4, 7, 14, 28
Find factor pairs that multiply to 28. 1 × 28 2 × 14 4 × 7
4. 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
5. 18
List factors of 54 and 18. The largest factor they share is 18.
6. 21
List factors of 21 and 21. The largest factor they share is 21.
7. 3
List factors of 9 and 21. The largest factor they share is 3.
8. 6
List factors of 12 and 30. The largest factor they share is 6.
9. 60
HCF(20, 12) = 4. LCM = 20 × 12 ÷ 4 = 60.
10. 42
HCF(14, 6) = 2. LCM = 14 × 6 ÷ 2 = 42.
11. 336
HCF(56, 48) = 8. LCM = 56 × 48 ÷ 8 = 336.
12. 45
HCF(9, 15) = 3. LCM = 9 × 15 ÷ 3 = 45.
Worked examples
List all the factors of 30.
- Find factor pairs that multiply to 30.
- 1 × 30
- 2 × 15
- 3 × 10
- 5 × 6
- Answer: 1, 2, 3, 5, 6, 10, 15, 30
Find the highest common factor (HCF) of 15 and 18.
- List factors of 15 and 18.
- The largest factor they share is 3.
- Answer: 3
Find the lowest common multiple (LCM) of 40 and 24.
- HCF(40, 24) = 8.
- LCM = 40 × 24 ÷ 8 = 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 in Context
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Learn — Meet the idea.
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Frequently asked
- Is this Grade 3 Prime Numbers in Context 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 Working with Prime Numbers, Introducing Prime Numbers, Multiples. 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 Prime Numbers in Context?
- Move on to Factors, Multiples, Prime Factorisation, HCF, which build directly on this idea.
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