15,30,45
Since 3 is a factor of 15, the first three common multiples of 3 and 15 are 15, 30, and 45.
15, 30, 45
15, 30, 45
15, 30, 45
15, 30, and 45 are.
15 & 20 have an infinite number of Common Multiples; the first three are 60, 120 and 180.
The LCM is: 90
105, 120, 135
9, 15, 21
60, 120, 180
135, 270, 405
60, 120, 180