Multiples that are shared by two or more numbers are COMMON MULTIPLES.
The least common multiple (LCM) is the smallest common multiple of two numbers, other than 0.
multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30
multiples of 6: 6, 12, 18, 24,30,36,42,48,54, 60
the common multiples of 3 and 6 are 6, 12, 18, 30
the least common multiple of 3 and 6 is 6.