What is the least common multiple of 12 and 24?

The least common multiple of 12 and 24 is 24. Since 24 is a multiple of 12, it is automatically the LCM of the set.
In arithmetic the least common multiple of two integers a and b, is the smallest positive integer that is divisible by both a and b. Therefore, the LCM of 12 and 24 is 24.