Examples
Example 1: Find the LCM of 15, 25 and 35.
Solution:
Prime factorization of 15: 15 = 3, 5
Prime factorization of 25: 25 = 5, 5
Prime factorization of 35: 35 = 5, 7
Take the common factors once and remaining unique factors.
Multiply them together to get LCM.
Therefore, LCM(15, 25, 35) = 525.
Example 2: 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 3: 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.
Exercise
1. LCM(12,15,18) = 180
2. LCM(20,30,40) = 120
3. LCM(36,48,72) = 144
4. LCM(10,12,15) = 60
5. LCM(6,7,21) = 42
6. LCM(12,24,30) = 120
7. LCM(2,3,9) = 18
8. LCM(4,6,12) = 12
9. LCM(9,16,34) = 2448
10. LCM(7,21,35) = 105