They are all multiples.
The Least Common Multiple (LCM) for 2 4 is 4.
No, they are just multiples of 2.
No, 2 and 28 are not multiples of 56, they are factors.
Use some method which you probably already learned, to find the least common multiple. All the other common multiples are multiples of this least common multiple, so you can multiply the least common multiple by 2, by 3, by 4, etc., to get additional common multiples.
The only Least Common Multiple (LCM) for 2 12 is 12.
The least common multiple of 2 , 3 and 11 is 66
To have an LCM, you need at least 2 numbers.
The LCM is: 52