We discuss common multiples of two (or more) integers.
Let a, b 
Z.
Definition
- The integer c is a common multiple of a and b if c is a multiple of a and of b (that is, a | c and b | c).
- The smallest nonnegative common multiple of a and b is called the least common multiple of a and b.
We express the least common multiple of a and b with lcm(a,b).