LCM( 9, 27, 28 ) = 756
Step 1: Write down factorisation of each number:
9 = 3 · 3
27 = 3 · 3 · 3
28 = 2 · 2 · 7
Step 2 : Match primes vertically:
9 | = | 3 | · | 3 | ||||||||
27 | = | 3 | · | 3 | · | 3 | ||||||
28 | = | 2 | · | 2 | · | 7 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
9 | = | 3 | · | 3 | ||||||||||
27 | = | 3 | · | 3 | · | 3 | ||||||||
28 | = | 2 | · | 2 | · | 7 | ||||||||
LCM | = | 2 | · | 2 | · | 3 | · | 3 | · | 3 | · | 7 | = | 756 |
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.