The LCM is 18. The greatest common multiple is infinite.
The least common multiples of the number 6 and 9 is 3.
Not all of them are. Consider 27. 6 and 9 share a lot of common multiples because they share a common factor.
Multiples of 90
18
Each common multiple of 9 and 10 occurs exactly once (in the list of common multiples), so there is no common multiple that occurs the most. All common multiples of 9 and 10 are the multiples of their least common multiple which is 90.
The common multiples of 6 and 9 are the infinite set of multiples of their LCM, which is 18. So the common multiples of 6 and 9 are 18, 36, 54, 72, 90, 108, 126, 144, 162, 180, and so on.
3
The first three multiples of 3 are 3, 6, 9 The first three multiples of 9 are 9, 18, 27 As the lowest common multiples of 3 and 9 is 9, the common multiples of 3 and 9 are the multiples of 9, thus: The first three common multiples of 3 and 9 are 9, 18, 27
The common multiples of 6 and 9 are the infinite set of multiples of their LCM, which is 18. So the common multiples of 6 and 9 are 18, 36, 54, 72, 90, 108, 126, 144, 162, 180, and so on.18, 36, 54 and so on.18, 36, 54 and so on.
The LCM of 6, 9, and 15 is 90.
There are plenty of common multiples, but only one can be the least; thus the least common multiple of 3, 6, 9 is 18.
The LCM is: 18