# What is the Greatest Common Factor of 5 and 18?

Greatest common factor (GCF) of 5 and 18 is 1.

GCF(5,18) = 1

We will now calculate the prime factors of 5 and 18, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 5 and 18.

GCF Calculator and
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## How to find the GCF of 5 and 18?

We will first find the prime factorization of 5 and 18. After we will calculate the factors of 5 and 18 and find the biggest common factor number .

### Step-1: Prime Factorization of 5

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

5 = 51

### Step-2: Prime Factorization of 18

Prime factors of 18 are 2, 3. Prime factorization of 18 in exponential form is:

18 = 21 × 32

### Step-3: Factors of 5

List of positive integer factors of 5 that divides 5 without a remainder.

1

### Step-4: Factors of 18

List of positive integer factors of 18 that divides 5 without a remainder.

1, 2, 3, 6, 9

#### Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 5 and 18. The biggest common factor number is the GCF number.
So the greatest common factor 5 and 18 is 1.

Also check out the Least Common Multiple of 5 and 18