# What is the Greatest Common Factor of 45 and 56?

Greatest common factor (GCF) of 45 and 56 is **1**.

GCF(45,56) = 1

We will now calculate the prime factors of **45 and 56**, than find the greatest common factor *(greatest common divisor (gcd))* of the numbers by matching the biggest common factor of 45 and 56.

## How to find the GCF of 45 and 56?

We will first find the prime factorization of 45 and 56. After we will calculate the factors of 45 and 56 and find the biggest common factor number .

### Step-1: Prime Factorization of 45

Prime factors of 45 are 3, 5. Prime factorization of **45** in exponential form is:

45 = 3^{2} × 5^{1}

### Step-2: Prime Factorization of 56

Prime factors of 56 are 2, 7. Prime factorization of **56** in exponential form is:

56 = 2^{3} × 7^{1}

### Step-3: Factors of 45

List of positive integer factors of 45 that divides 45 without a remainder.

1, 3, 5, 9, 15

### Step-4: Factors of 56

List of positive integer factors of 56 that divides 45 without a remainder.

1, 2, 4, 7, 8, 14, 28

#### Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 45 and 56. The biggest common factor number is the **GCF** number.

So the **greatest common factor 45 and 56** is **1**.

Also check out the Least Common Multiple of 45 and 56