OK, I felt a little guilty for not giving a better answer.
Think of the problem this way. You need to find the lowest common multiple of several numbers. So I start by finding the lowest and highest number in that range. Now, you know that whatever this lcm is, it must be a multiple of the largest number in the range (let's call that max).
So I would start with lcm set to the largest number in the range, then I would loop to see if all the other numbers can evenly divide into it. As soon as any of those numbers can't divide into lcm, then I know I can break out of the loop and try the next candidate lcm. And I just keep adding max to my previous candidate lcm - remember that our final lcm must be a multiple of max (and all the other numbers, but max is the biggest so let's index by that.) If you ever get through your whole range of numbers from min to max-1 (no need to check max since we're indexing by it) then we know we've found our lcm.
I hope that helps without giving too much away.