# What is the Greatest Common Factor of 4 and 9?

Greatest common factor (GCF) of 4 and 9 is **1**.

GCF(4,9) = 1

We will now calculate the prime factors of **4 and 9**, than find the greatest common factor *(greatest common divisor (gcd))* of the numbers by matching the biggest common factor of 4 and 9.

## How to find the GCF of 4 and 9?

We will first find the prime factorization of 4 and 9. After we will calculate the factors of 4 and 9 and find the biggest common factor number .

### Step-1: Prime Factorization of 4

Prime factors of 4 are 2. Prime factorization of **4** in exponential form is:

4 = 2^{2}

### Step-2: Prime Factorization of 9

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

9 = 3^{2}

### Step-3: Factors of 4

List of positive integer factors of 4 that divides 4 without a remainder.

1, 2

### Step-4: Factors of 9

List of positive integer factors of 9 that divides 4 without a remainder.

1, 3

#### Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 4 and 9. The biggest common factor number is the **GCF** number.

So the **greatest common factor 4 and 9** is **1**.

Also check out the Least Common Multiple of 4 and 9