# What is the Greatest Common Factor of 40 and 55?

Greatest common factor (GCF) of 40 and 55 is 5.

GCF(40,55) = 5

We will now calculate the prime factors of 40 and 55, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 40 and 55.

GCF Calculator and
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## How to find the GCF of 40 and 55?

We will first find the prime factorization of 40 and 55. After we will calculate the factors of 40 and 55 and find the biggest common factor number .

### Step-1: Prime Factorization of 40

Prime factors of 40 are 2, 5. Prime factorization of 40 in exponential form is:

40 = 23 × 51

### Step-2: Prime Factorization of 55

Prime factors of 55 are 5, 11. Prime factorization of 55 in exponential form is:

55 = 51 × 111

### Step-3: Factors of 40

List of positive integer factors of 40 that divides 40 without a remainder.

1, 2, 4, 5, 8, 10, 20

### Step-4: Factors of 55

List of positive integer factors of 55 that divides 40 without a remainder.

1, 5, 11

#### Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 40 and 55. The biggest common factor number is the GCF number.
So the greatest common factor 40 and 55 is 5.

Also check out the Least Common Multiple of 40 and 55