Write an article based on this "Create a factor tree for each number in the set. Identify all of the common factors. Multiply the common factors together. Write your answer."
To find the greatest common factor (GCF) between two or more numbers, you need to start by breaking down each number into its prime number factors. You can use the factor tree method to do this.  You will need to create a separate factor tree for each number. The process required for making a factor tree is the same as described in the “Making a Factor Tree” section. The GCF between two or more numbers is the largest prime number factor that is shared between all of the given numbers in the problem. This number must divide evenly into all of the original numbers in the problem.  Example: Find the GCF of 195 and 260.  ......195 ....../....\ ....5....39 ........./....\ .......3.....13 The prime factors of 195 are: 3, 5, 13 .......260 ......./.....\ ....10.....26 .../...\ …/..\ .2....5...2...13 The prime factors of 260 are: 2, 2, 5, 13 Look at all of the factor trees created for your original values. Identify the prime factors of each original number, then highlight or write down all of the factor numbers that both lists have in common  If there are no common factors between the numbers, the GCF is the number 1.  Example: As noted previously, the factors of 195 are 3, 5, and 13; the factors of 260 are 2, 2, 5, and 13. The common factors between both numbers are 5 and 13. When two or more numbers have more than one common factor between them, you must find the GCF by multiplying all of the shared factors together.  If there is only one shared factor between two or more numbers, however, the GCF is simply that single shared factor.  Example: The common factors between 195 and 260 are 5 and 13. The product of 5 multiplied by 13 is 65. 5 * 13 = 65 The problem is now complete, and you should have your answer ready.  You can double-check your work, if desired, by dividing each of your original numbers by the GCF you calculated. If the GCF goes into each number evenly, the solution should be accurate.  Example: The greatest common factor (GCF) of 195 and 260 is 65.  195 / 65 = 3 260 / 65 = 4