LCM( 1, 2, 3, 4 ) = 12
Step 1: Write down factorisation of each number:
1 = 1
2 = 2
3 = 3
4 = 2 · 2
Step 2 : Match primes vertically:
1 | = | 1 | ||||||
2 | = | 2 | ||||||
3 | = | 3 | ||||||
4 | = | 2 | · | 2 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
1 | = | 1 | ||||||||
2 | = | 2 | ||||||||
3 | = | 3 | ||||||||
4 | = | 2 | · | 2 | ||||||
LCM | = | 1 | · | 2 | · | 2 | · | 3 | = | 12 |