Examples
Example 1: Find the LCM of 9 and 12.
Solution:
Prime factors of 9 = 3, 3
Prime factors of 12 = 2, 2, 3
Write these prime factors into the venn diagram for each number.
Multiply each prime factor in the venn diagram to find the LCM.
Therefore, LCM(9, 12) = 36.
Example 2: Find the LCM of 24 and 36.
Solution:
Prime factors of 24 = 2, 2, 2, 3
Prime factors of 36 = 2, 2, 3, 3
Write these prime factors into the venn diagram for each number.
Multiply each prime factor in the venn diagram to find the LCM.
Therefore, LCM(24, 36) = 72.
Example 3: Find the LCM of 40 and 56.
Solution:
Prime factors of 40 = 2, 2, 2, 5
Prime factors of 56 = 2, 2, 2, 7
Write these prime factors into the venn diagram for each number.
Multiply each prime factor in the venn diagram to find the LCM.
Therefore, LCM(40, 56) = 280.
Exercise
1. LCM(4,6) = 12
2. LCM(10,25) = 50
3. LCM(20,35) = 140
4. LCM(12, 36) = 36
5. LCM(45,75) = 225
6. LCM(35, 15) = 105
7. LCM(16, 20) = 80
8. LCM(15, 45) = 45
9. LCM(48, 60) = 240
10. LCM(30, 45) = 90