# How to find gcf and lcm

## Greatest common factor explained To find either the Least Common Multiple (LCM) or Greatest Common Factor ( GCF) of two numbers, you always start out the same way: you find the prime.

and   get   season episode   watch

With a little bit of help the students were able to come up with definitions for each of them and described the method they had used in the past to find the greatest common factor and least common multiple of two numbers. Previously the students had learned to list all the factors of 2 numbers and find the largest one they had in common. Similarly, to find the least common multiple, the class had learned to list multiples of the numbers until they found one in common. Then we discussed the limitations of this method for finding the GCF and LCM, mainly the fact that if I gave them much larger numbers it would be very time-consuming to list all the factors or list multiples until they found one in common. You then find ANY common factor of the two numbers and write that factor to the left of them. You then divide the numbers by their common factor and write the quotients underneath the numbers.

If you're seeing this message, it means we're having trouble loading external resources on our website. To log in and use all the features of Khan Academy, please enable JavaScript in your browser. Math Pre-algebra Factors and multiples Greatest common factor. Greatest common factor examples. Greatest common factor explained. Practice: Greatest common factor. Current timeTotal duration

Ask Dr. Common multiples of 2 and 3 are 0, 6, 12, 18, The least common multiple LCM of two numbers is the smallest number excluding zero that is a multiple of both of the numbers. Here are two least common multiple questions from the Dr. Math archives: Least Common Multiple Puzzle What is the smallest number divisible by 1,2,3,4,5,6,8,9,10 that is not ?

If you're seeing this message, it means we're having trouble loading external resources on our website. To log in and use all the features of Khan Academy, please enable JavaScript in your browser. Math Pre-algebra Factors and multiples Greatest common factor. Greatest common factor examples. Greatest common factor explained. Practice: Greatest common factor.

## GCF & LCM word problems

Then here's the trick!, Every whole number greater than 1 has a prime factorization — that is, the list of prime numbers including repeats that equal that number when multiplied together.

.

## Find the LCM and the GCF of Integers - Examples and Questions with Answers (Grade 5)

.

.

.

.

1. Leo B. says:
2. Natasha H. says:
3. Claslanniro1963 says: