# What is the Greatest Common Factor of 9 and 20?

Greatest common factor (GCF) of 9 and 20 is 1.

GCF(9,20) = 1

We will now calculate the prime factors of 9 and 20, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 9 and 20.

GCF Calculator and
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## How to find the GCF of 9 and 20?

We will first find the prime factorization of 9 and 20. After we will calculate the factors of 9 and 20 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 = 32

### Step-2: Prime Factorization of 20

Prime factors of 20 are 2, 5. Prime factorization of 20 in exponential form is:

20 = 22 × 51

### Step-3: Factors of 9

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

1, 3

### Step-4: Factors of 20

List of positive integer factors of 20 that divides 9 without a remainder.

1, 2, 4, 5, 10

#### Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 9 and 20. The biggest common factor number is the GCF number.
So the greatest common factor 9 and 20 is 1.

Also check out the Least Common Multiple of 9 and 20