630, 945, 1260, 1575, 1890, 2205
315, 630, 945, 1260, 1575 . . .
There are an infinite number of common multiples for 7 and nine. Some of them are 63, 126, 189, 252, 315, and 378.63
Here are some multiples of both 15 and 7: 105, 210, 315, 420, 525, 630, 735, 840, 945.
Any multiple of 315.
315
Two common multiples of 21 and 15 are 105 and 315.
315
105, 210, 315
105, 210, 315 and so on.
63, 126, 189, 252, 315.
Multiples of 105 include 105, 210, 315 and so on. For them to be common, they need to be compared to another set of multiples.
105, 210, 315