The greatest common factor (GCF) is the largest number that divides both numbers. There are two methods to find the GCF: listing the factors of each number, where the GCF is the largest shared factor, or using a ladder method where you divide both numbers by their common prime factors until only one number remains. The document provides examples of finding the GCF of 18 and 30 by listing factors, and of 27 and 36 using the ladder method.

1. Finding the Greatest Common Factor

2. The greatest common factor of two or more numbers is the greatest number that is a factor of every number.

3. There are two methods for finding the GCF.1. Listing the factors2. Using the Ladder

4. To find the GCF of two numbers using a list, list the factors of one number. Then list the factors of the second number. The GCF is the greatest value that appears on both lists.

5. 1. Make a list to find the GCF of 18 and 3018: 1, 2, 3, 6, 9, 1830: 1, 2, 3, 5, 6, 10, 15, 30THE GCF of 18 and 30 is 6.

6. To find the GCF of two numbers using the ladder method, determine a prime number that you can divide evenly into each number. Write the number on the side and divide. Continue as far as you can!

7. 2. Use a ladder to find the GCF of 27 and 363 27 36 3 x 3 =9 so the GCF is 99 123 3 4