LCM( 42, 81 ) = 1134
Step 1: Write down factorisation of each number:
42 = 2 · 3 · 7
81 = 3 · 3 · 3 · 3
Step 2 : Match primes vertically:
42 | = | 2 | · | 3 | · | 7 | ||||||
81 | = | 3 | · | 3 | · | 3 | · | 3 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
42 | = | 2 | · | 3 | · | 7 | ||||||||
81 | = | 3 | · | 3 | · | 3 | · | 3 | ||||||
LCM | = | 2 | · | 3 | · | 3 | · | 3 | · | 3 | · | 7 | = | 1134 |
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.