if you are having trouble with the least common multiple all you do is take the numbers like if it was 6 10 and 3 you would do this
Steps:
1.) 6,12,24,30,34
10,20,30,40
3,6,9,12,15,18,21,24,27,30
2.) look for the number that is in common but the smallest
3.) then you have the answer