LCM( 3, 7, 2, 12 ) = 84
Step 1: Write down factorisation of each number:
3 = 3
7 = 7
2 = 2
12 = 2 · 2 · 3
Step 2 : Match primes vertically:
| 3 | = | 3 | ||||||
| 7 | = | 7 | ||||||
| 2 | = | 2 | ||||||
| 12 | = | 2 | · | 2 | · | 3 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
| 3 | = | 3 | ||||||||
| 7 | = | 7 | ||||||||
| 2 | = | 2 | ||||||||
| 12 | = | 2 | · | 2 | · | 3 | ||||
| LCM | = | 2 | · | 2 | · | 3 | · | 7 | = | 84 |