The multiples of 10 are 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120 etc.....
The multiples of 15 are 15, 30, 45, 60, 75, 90, 105, 120, 135 etc......
Some of these multiples appear in both lists and these are the common multiples of 10 and 15. They are:
30, 60, 90, 120 etc.
This list will go on forever but 30 is the smallest or the lowest common multiple (LCM) of 10 and 15.
Does that make sense?
Let's try some questions now.