Examples
Example 1: Find the LCM of 2, 5 and 8.
Solution:
LCM of 2 and 5:
Multiples of 2 = 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, ...
Multiples of 5 = 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, ...
Multiples of 8 = 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, ...
Smallest common multiple is 40.
Therefore, LCM(2, 5, 8) = 40.
Example 2: Find the LCM of 12, 16 and 20.
Solution:
LCM of 12 and 16:
Multiples of 12 = 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, ...
Multiples of 16 = 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, ...
Multiples of 20 = 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, ...
Smallest common multiple is 240.
Therefore, LCM(12, 16, 20) = 240.
Example 3: Find the LCM of 8, 10 and 12.
Solution:
LCM of 8 and 10:
Multiples of 8 = 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, ...
Multiples of 10 = 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, ...
Multiples of 12 = 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, ...
Smallest common multiple is 120.
Therefore, LCM(8, 10, 12) = 120.
Exercise
1. LCM(3,5,7) = 105
2. LCM(8,10,12) = 120
3. LCM(12,16,20) = 240
4. LCM(18,24,10) = 360
5. LCM(30,40,25) = 600
6. LCM(4,5,8) = 40
7. LCM(9,12,16) = 144
8. LCM(6,8,16) = 48
9. LCM(5,11,13) = 715
10. LCM(30,45,150) = 450