To find the least common multiple (LCM) of 3 and 9, we can list the multiples of each number:
Multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27, ... Multiples of 9: 9, 18, 27, 36, ...
The smallest multiple that appears in both lists is 9.
Therefore, the least common multiple of 3 and 9 is 9.