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
60
75
15 & 20 have an infinite number of Common Multiples; the first three are 60, 120 and 180.
15 and 30
15, 30, 45
Multiples of 5 include 5, 10 and 15. For them to be common, they need to be compared to another set of multiples.
Multiples of 15 include 15, 30 and 45. For them to be common, they need to be compared to another set of multiples.
30 and 60
60, 120, 180
105 and 210