LCM( 14, 28, 21 ) = 84
Step 1 : Write the given numbers in a horizontal line.
| 14 | 28 | 21 |
Step 2 : Divide the given numbers by smallest prime number. In this example we can divide by 2.
(if any number is not divisible by 2, write it down unchanged)
| 2 | 14 | 28 | 21 |
| 7 | 14 | 21 |
Step 3 : Continue dividing by prime numbers till we get 1 in all columns.
| 2 | 14 | 28 | 21 |
| 2 | 7 | 14 | 21 |
| 3 | 7 | 7 | 21 |
| 7 | 7 | 7 | 7 |
| 1 | 1 | 1 |
Step 4 : Multiply numbers in first column to get LCM.
LCM( 14, 28, 21 ) = 2 · 2 · 3 · 7 = 84 .
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.