LCM( 5, 4, 1 ) = 20
Write down multiples of each number until you find the first common multiple:
The multipliers of 5 are: 5, 10, 15, 20, 25, . . .
The multipliers of 4 are: 4, 8, 12, 16, 20, 24, . . .
The multipliers of 1 are: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, . . .
We can see that:
LCM( 5, 4, 1 ) = 20
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.