40, 80, 120
30
Because 9 is a multiple of 3, the common multiples of 3 and 9 are the multiples of 9. The first 10 common multiples of 3 and 9 are 9, 18, 27, 36, 45, 54, 63, 72, 81, and 90.
Any multiple of 30.
It is: 120
Common denominators. These are called "common multiples". For example, multiples of 4 are: 4,8,12,16,20,24 ... . Multiples of 6 are: 6,12,18,24,30,36 ... . The numbers on both lists are the common multiples and they include: 12,24,36, ... . Specifically, the smallest number in any such list of common multiples (12 in this example) is known as the Least (or Lowest) Common Multiple or LCM.
The common multiples of 3,4, and 10 would be all the multiples of 60. 60, 120, 180, 240... all the way to 6000.
30, 60 and 90
10, 20 and 30
They are: 30, 60 and 90
4, 6 and 10
5
1 11 10