This week in Math 10, I’d say the most important thing we learned was how to find the LCM (lowest common multiple) and the GCF (greatest common factor) of multiple numbers using prime factorization.

Steps to find LCM:

The first step is to find all the factors of both numbers. In my opinion, the easiest way is with a factor tree. Simply write your number and then write beneath it the 2 numbers that multiply into your number, for example:

After finishing the tree, write down all the factors in an equation like this:

Make sure to do the same for both numbers and then you want to compare them and circle each number the 2 have in common but only vertically or diagonally, you can not do sideways

After, make an equation with the numbers that were circled and then put them in brackets, after that you can add the rest of the numbers to the equation but outside of the brackets like this. Multiply them all and you have your answer.\\

For the GCF it is basically the same except after you write the equation you remove any numbers without a pair from the equation, for example: