4
144
240
There is no "most common" multiple of two or more numbers, but there is a greatest common multiple if that's what you mean. But for multiples, the list of common ones goes on and on and on, since every single number in the universe is a multiple.
48
six sixteenths, twelve thirtyseconds, twentyfour sixtyfourths
Zero and twelve don't have any common multiples.
twelve and two fifth
(improved by:hoseyjames35) answer:192
120
60
12
72