Theory:

Common multiple
A multiple (product), which is common to two or more numbers is called a common multiple.
Example:
1. Find the first common multiple of the numbers \(8\), \(9\) and \(12\).
 
GIF_8_9_12.gif
 
The first common multiple of \(8\), \(9\) and \(12\) is \(72\).
 
 
2. List first four common multiples of \(3\) and \(6\).
 
GIF_3_6.gif
 
The first our common multiples of \(3\) and \(6\) are \(6\), \(12\), \(18\) and \(24\).