Answer:
72
Explanation:
The LCM is the least common multiple
So we can start out by listing multiples.
The first number that we see that is common amongst all the numbers is the LCM
8: 16, 24, 32, 40, 48, 56, 64, 72
12: 24, 36, 48, 60, 72, 84, 96
18: 36, 54, 72, 90
72 is the smallest multiple shared amongst 8, 12 and, 18.