LCM( 5, 6, 9 ) = 90
Step 1: Write down factorisation of each number:
5 = 5
6 = 2 · 3
9 = 3 · 3
Step 2 : Match primes vertically:
5 | = | 5 | ||||||
6 | = | 2 | · | 3 | ||||
9 | = | 3 | · | 3 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
5 | = | 5 | ||||||||
6 | = | 2 | · | 3 | ||||||
9 | = | 3 | · | 3 | ||||||
LCM | = | 2 | · | 3 | · | 3 | · | 5 | = | 90 |
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.