The way to derive the Highest Common Factor & Lowest Common Multiple can be trick. Especially when you have to find the LCM of larger numbers such as lets say 165 & 220. You effectively have to do your 165 and 220 times tables to get to the answer!
Or do you?
There is a quicker root per the attached word document I created
It has a technique which will assist greatly
The answer to the above BTW , is 660!!https://123tutors.co.uk/finding-the-lowest-common-denominator/