Multiples of 105 include 105, 210, 315 and so on. For them to be common, they need to be compared to another set of multiples.
210
12
It is 30
It is 42
It is: 90
It is 20
315
The LCM is 24.
The Least Common Multiple (LCM) for12 9is36
The Least Common Multiple (LCM) for 28 90 is 1,260.
20 and 30 among others.
They're all prime numbers, therefore it's one.