Write down multiples of each number until you find the first common multiple:

The multipliers of 2 are: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, . . .

The multipliers of 5 are: 5, 10, 15, 20, 25, 30, 35, 40, 45, . . .

The multipliers of 8 are: 8, 16, 24, 32, 40, 48, . . .

We can see that:

LCM( 2, 5, 8 ) = 40

This solution can be visualized using a Venn diagram.

The LCM is equal to the product of all the numbers on the diagram.