What is the GCF of 36 and 84? Find the prime factorization of 36. Find the prime factorization of 84. 84 = 2 × 2 × 3 × 7. To find the GCF, multiply all the prime factors common to both numbers: Therefore, GCF = 2 × 2 × 3. GCF = 12. 1, 2, 3, 4, 6, 9, 12, 18, and 36. 1, 2, 3, 6, 9, 18, 27, and 54. Although the numbers in bold are all common factors of both 36 and 54, 18 is the greatest common factor. The second method to find the greatest common factor is to list the prime factors, then multiply the common prime factors. Greatest Common Factor and Greatest Common Divisor The TI-84 Plus CE will find the GCF/GCD of two numbers. Example 1: To find the GCF of 24 and 30, press math, arrow over to NUM, and select 9:gcd( —either by moving the cursor down to option 9 and pressing enter, or by simply pressing 9). Greatest common factor (GCF) of 36 and 47 is 1. We will now calculate the prime factors of 36 and 47, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 36 and 47. Example 4: Find the GCF of 24 and 36. The common factors of 24 and 36 are 1, 2, 3, 4, 6 and 12. The greatest common factor of 24 and 36 is 12. The common factors for 20,24,40 20 , 24 , 40 are 1,2,4 1 , 2 , 4 . The GCF (HCF) of the numerical factors 1,2,4 1 , 2 , 4 is 4.
