LCM( 20, 26, 28 ) = 1820
Step 1: Write down factorisation of each number:
20 = 2 · 2 · 5
26 = 2 · 13
28 = 2 · 2 · 7
Step 2 : Match primes vertically:
20 | = | 2 | · | 2 | · | 5 | ||||
26 | = | 2 | · | 13 | ||||||
28 | = | 2 | · | 2 | · | 7 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
20 | = | 2 | · | 2 | · | 5 | ||||||
26 | = | 2 | · | 13 | ||||||||
28 | = | 2 | · | 2 | · | 7 | ||||||
LCM | = | 2 | · | 2 | · | 5 | · | 7 | · | 13 | = | 1820 |
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.