# What is the Greatest Common Factor of 9 and 25?

Greatest common factor (GCF) of 9 and 25 is **1**.

GCF(9,25) = 1

We will now calculate the prime factors of **9 and 25**, than find the greatest common factor *(greatest common divisor (gcd))* of the numbers by matching the biggest common factor of 9 and 25.

## How to find the GCF of 9 and 25?

We will first find the prime factorization of 9 and 25. After we will calculate the factors of 9 and 25 and find the biggest common factor number .

### Step-1: Prime Factorization of 9

Prime factors of 9 are 3. Prime factorization of **9** in exponential form is:

9 = 3^{2}

### Step-2: Prime Factorization of 25

Prime factors of 25 are 5. Prime factorization of **25** in exponential form is:

25 = 5^{2}

### Step-3: Factors of 9

List of positive integer factors of 9 that divides 9 without a remainder.

1, 3

### Step-4: Factors of 25

List of positive integer factors of 25 that divides 9 without a remainder.

1, 5

#### Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 9 and 25. The biggest common factor number is the **GCF** number.

So the **greatest common factor 9 and 25** is **1**.

Also check out the Least Common Multiple of 9 and 25