Examples
Example 1: Find the LCM of 8, 4 and 6.
Solution:
Prime factorization of 8: 8 = 2, 2, 2
Prime factorization of 4: 4 = 2, 2
Prime factorization of 6: 6 = 2, 3
Take the common factors once and remaining unique factors.
Multiply them together to get LCM.
Therefore, LCM(8, 4, 6) = 24.
Example 2: Find the LCM of 6, 12 and 18.
Solution:
Prime factorization of 6: 6 = 2, 3
Prime factorization of 12: 12 = 2, 2, 3
Prime factorization of 18: 18 = 2, 3, 3
Take the common factors once and remaining unique factors.
Multiply them together to get LCM.
Therefore, LCM(6, 12, 18) = 36.
Example 3: Find the LCM of 8, 12 and 30.
Solution:
Prime factorization of 8: 8 = 2, 2, 2
Prime factorization of 12: 12 = 2, 2, 3
Prime factorization of 30: 30 = 2, 3, 5
Take the common factors once and remaining unique factors.
Multiply them together to get LCM.
Therefore, LCM(8, 12, 30) = 90.
Exercise
1. LCM(12,18,24) = 72
2. LCM(20,30) = 60
3. LCM(15,20,25,30) = 300
4. LCM(12,24,30) = 120
5. LCM(3,9,18) = 18
6. LCM(4,6,12) = 12
7. LCM(6,7,21) = 42
8. LCM(5,9,18) = 90
9. LCM(4,7,14) = 28
10. LCM(4,24,21) = 168