30
It is: 120
The common multiples of 3,4, and 10 would be all the multiples of 60. 60, 120, 180, 240... all the way to 6000.
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.
30, 60 and 90
Common multiples of 9 and 10 are all of the multiples of 90.
They are: 30, 60 and 90
4, 6 and 10
15,18,21,24,27,30,33,36,39,42,45,48,51,54,57,60,63,66,69,72,75,78,81,84,87,90,93,96,99
5
1 11 10
10, 20 and 30