LCM( 15, 21, 33, 54 ) = 20790
Step 1: Write down factorisation of each number:
15 = 3 · 5
21 = 3 · 7
33 = 3 · 11
54 = 2 · 3 · 3 · 3
Step 2 : Match primes vertically:
15 | = | 3 | · | 5 | ||||||||||
21 | = | 3 | · | 7 | ||||||||||
33 | = | 3 | · | 11 | ||||||||||
54 | = | 2 | · | 3 | · | 3 | · | 3 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
15 | = | 3 | · | 5 | ||||||||||||
21 | = | 3 | · | 7 | ||||||||||||
33 | = | 3 | · | 11 | ||||||||||||
54 | = | 2 | · | 3 | · | 3 | · | 3 | ||||||||
LCM | = | 2 | · | 3 | · | 3 | · | 3 | · | 5 | · | 7 | · | 11 | = | 20790 |