LCM
Another way to find the LCM is a method similar to the division table. By using this table you only need to use prime factorization once, for all the numbers at the same time.
The numbers I used were 220,117,108
You have to make a table and put all of the numbers you are trying to find the LCM for in one column. Then you divide by prime numbers in the other column. It doesn’t matter if all of the numbers divide by that number, you can just carry the number that is not divisible by the number you are trying to divide by down to the next row. You just need to remember to only divide by prime numbers.
In the end you multiply all of the prime numbers in the column and that should give you the LCM. 
GCF
In this method you put all of the nu
mbers you are trying to find the GCF in one column. Then you start dividing the numbers by prime numbers. You have to find a number that is divisible by all of the numbers for this method. Then at the end you multiply all of the prime numbers you got.
I personally prefer the method we learnt in class because, it is easier. For the LCM your basically just doing the same amount of work but taking up less space, but this method confused me quite a lot. I also prefer the method we learnt in class for the GCF because in the method I found online you have to find a number that is a factor for both of the numbers that you are trying to find the GCF for. Overall the methods in class were much easier then the ones I have found online.