### 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 $$12$$.

The first common multiple of $$8$$, $$9$$ and $$12$$ is $$72$$.

2. List first four common multiples of $$3$$ and $$6$$.

The first our common multiples of $$3$$ and $$6$$ are $$6$$, $$12$$, $$18$$ and $$24$$.