They are the six multiples of 15.
The multiples of 15 are 15, 30, 45, 60, 75 and so on. For them to be common, they need to be compared to another set of multiples.
The common multiples of 15 and 16 are 240, 480, 720 and so on.
Two common multiples of 21 and 15 are 105 and 315.
There are infinite common multiples for a set of numbers. So it is not possible to write down all the common multiples. Some common multiples of 15, 30 and 45 are 90, 180, 270, 360,... There is another way to find common multiples: Write the multiples of LCM(15, 30, 45). Actually the common multiples of a set of numbers are the multiples of their LCM. LCM of 15, 30 and 45 is 90. And the multiples of 90 are 90, 180, 270, 360, 450, 540,... which are the common multiples of 15, 30 and 45.
Multiples of 15 include 15, 30 and 45. For them to be common, they need to be compared to another set of multiples.
A word problem that involves common multiples could be, "Whatare the common multiples of 10 and 15?"
15, 30, 45,60,75,and 90
Since 3 is a factor of 15, the first three common multiples of 3 and 15 are 15, 30, and 45.
the first two common multiples of 15,27 are 135,270
All multiples of 90.
30 and all its multiples