I would draw a Venn diagram. Draw circles for numbers divisible by 2, by 3 and by 5.

The various intersections contain numbers divisible

by 2 and by 3 [these are divisible by 6]

by 2 and by 5 [these are divisible by 10]

by 3 and by 5 [these are divisible by 15]

and the intersection of all three has numbers divisible by 2, by 3 and by 5 [these are divisible by 30].