LCM( 1400, 2100 ) = 4200
Step 1: Write down factorisation of each number:
1400 = 2 · 2 · 2 · 5 · 5 · 7
2100 = 2 · 2 · 3 · 5 · 5 · 7
Step 2 : Match primes vertically:
1400 | = | 2 | · | 2 | · | 2 | · | 5 | · | 5 | · | 7 | ||
2100 | = | 2 | · | 2 | · | 3 | · | 5 | · | 5 | · | 7 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
1400 | = | 2 | · | 2 | · | 2 | · | 5 | · | 5 | · | 7 | ||||
2100 | = | 2 | · | 2 | · | 3 | · | 5 | · | 5 | · | 7 | ||||
LCM | = | 2 | · | 2 | · | 2 | · | 3 | · | 5 | · | 5 | · | 7 | = | 4200 |
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.