LCM( 4, 6, 8, 9 ) = 72
Step 1: Write down factorisation of each number:
4 = 2 · 2
6 = 2 · 3
8 = 2 · 2 · 2
9 = 3 · 3
Step 2 : Match primes vertically:
4 | = | 2 | · | 2 | ||||||
6 | = | 2 | · | 3 | ||||||
8 | = | 2 | · | 2 | · | 2 | ||||
9 | = | 3 | · | 3 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
4 | = | 2 | · | 2 | ||||||||
6 | = | 2 | · | 3 | ||||||||
8 | = | 2 | · | 2 | · | 2 | ||||||
9 | = | 3 | · | 3 | ||||||||
LCM | = | 2 | · | 2 | · | 2 | · | 3 | · | 3 | = | 72 |