Answer
120
Work Step by Step
Multiples of 6 : 6,12,18,24,30,36,42,48,54,60,66,72,78,84,90,96,102,108,114,120.
Multiples of 8 = 8,16,24,32,40,48,56,64,72,80,88,96,104,112,120
Multiples of 10 : 10,20,30,40,50,60,70,80,90,100,100,110,120
Multiples of 12 : 12,24,36,48,60,72,84,96,108,120
Now 120 is the smallest common number in all the lists. so 120 is LCM 6, 8, 10, 12.