LCM( 21, 35 ) = 105
Write down multiples of each number until you find the first common multiple:
The multipliers of 21 are: 21, 42, 63, 84, 105, 126, . . .
The multipliers of 35 are: 35, 70, 105, 140, . . .
We can see that:
LCM( 21, 35 ) = 105
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.