Answer: 60
Explanation:
write down the 12 times table
12 , 24, 36, 48, 60, 72, 84, 96, 108, 120
20, 40, 60, 80, 100, 120, 140, 160, 180, 200
Now you can see that 60 is the multiple that comes up first in both of the times tables which means it is the lowest common factor.