LCM( 640, 680, 860 ) = 467840
Step 1 : Write the given numbers in a horizontal line.
| 640 | 680 | 860 |
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 | 640 | 680 | 860 |
| 320 | 340 | 430 |
Step 3 : Continue dividing by prime numbers till we get 1 in all columns.
| 2 | 640 | 680 | 860 |
| 2 | 320 | 340 | 430 |
| 2 | 160 | 170 | 215 |
| 2 | 80 | 85 | 215 |
| 2 | 40 | 85 | 215 |
| 2 | 20 | 85 | 215 |
| 2 | 10 | 85 | 215 |
| 5 | 5 | 85 | 215 |
| 17 | 1 | 17 | 43 |
| 43 | 1 | 1 | 43 |
| 1 | 1 | 1 |
Step 4 : Multiply numbers in first column to get LCM.
LCM( 640, 680, 860 ) = 2 · 2 · 2 · 2 · 2 · 2 · 2 · 5 · 17 · 43 = 467840 .
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.