Let’s solve each problem step by step. We’re finding the
Least Common Multiple (LCM) — that means the smallest number that both numbers can divide into evenly.
---
1a. 4, 2
Multiples of 4: 4, 8, 12, 16...
Multiples of 2: 2, 4, 6, 8, 10...
→ First common multiple is
4
✔ LCM = 4
---
1b. 3, 9
Multiples of 3: 3, 6, 9, 12...
Multiples of 9: 9, 18, 27...
→ First common multiple is
9
✔ LCM = 9
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2a. 10, 11
These are consecutive numbers and don’t share any factors except 1. So we multiply them:
10 × 11 =
110
✔ LCM = 110
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2b. 4, 6
Multiples of 4: 4, 8, 12, 16...
Multiples of 6: 6, 12, 18...
→ First common multiple is
12
✔ LCM = 12
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3a. 5, 4
No common factors → multiply: 5 × 4 =
20
✔ LCM = 20
---
3b. 6, 3
6 is already a multiple of 3 → so LCM is
6
✔ LCM = 6
---
4a. 3, 9
Same as 1b → 9 is multiple of 3 → LCM =
9
✔ LCM = 9
---
4b. 11, 5
Both prime, no common factors → 11 × 5 =
55
✔ LCM = 55
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5a. 12, 8
List multiples:
Multiples of 12: 12, 24, 36...
Multiples of 8: 8, 16, 24, 32...
→ First common multiple is
24
✔ LCM = 24
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5b. 7, 4
No common factors → 7 × 4 =
28
✔ LCM = 28
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Final Answer:
1a. 4
1b. 9
2a. 110
2b. 12
3a. 20
3b. 6
4a. 9
4b. 55
5a. 24
5b. 28
Parent Tip: Review the logic above to help your child master the concept of gcf and lcm worksheet.
