Answer:
Step-by-step explanation:
Put these numbers into their prime factors.
18: 2 * 3 * 3
27: 3 * 3 * 3
12: 2 * 2 * 3
The LCM must have
two 2s
Three 3s
That's it
2*2 * 3 * 3 * 3
LCM = 108
648 might be a multiple of the three, but it's not the smallest one.
108 = 27 * 4
108 = 18 * 6
108 = 12 * 9
