LCM( 6, 7, 4, 9 ) = 252
Step 1: Write down factorisation of each number:
6 = 2 · 3
7 = 7
4 = 2 · 2
9 = 3 · 3
Step 2 : Match primes vertically:
| 6 | = | 2 | · | 3 | ||||||
| 7 | = | 7 | ||||||||
| 4 | = | 2 | · | 2 | ||||||
| 9 | = | 3 | · | 3 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
| 6 | = | 2 | · | 3 | ||||||||
| 7 | = | 7 | ||||||||||
| 4 | = | 2 | · | 2 | ||||||||
| 9 | = | 3 | · | 3 | ||||||||
| LCM | = | 2 | · | 2 | · | 3 | · | 3 | · | 7 | = | 252 |