What is the GCF of 5 and 9?
GCF (Greatest Common Factor) of 5 and 9 is the greatest possible number which divides 5 and 9 exactly without any remainder.
Answer: GCF of 5 and 9 is 1
Lets see how to find the GCF of 5 and 9
Explanation
We can find the GCF by the following methods.
 Prime factorization Method
 Long division Method
GCF of 5 and 9 by Prime Factorization
Let us represent 5 and 9 as a product of their prime numbers:
Prime factorization of 5 is 1 × 5
Prime factorization of 9 is 1 × 3 × 3
1 is the only common factor in the prime factorization of 5 and 9
GCF is the product of the prime factors that are common to prime factorization of 5 and 9
So, the GCF of 5 and 9 is 1
GCF of 5 and 9 by Long Division Method

Step 1: Divide 5 by 9 and check the remainder. Here, the remainder is 4

Step 2: Make the remainder 4 as the divisor and the divisor 5 as the dividend and perform the long division again.

Step 3: Continue till you get the remainder as 0 and GCF of 5 and 9 will be the last divisor.
You can find the GCF of 5 and 9 in any of the above methods but the solution will always remain the same.