# What is the Greatest Common Factor of 42 and 49?

Greatest common factor (GCF) of 42 and 49 is 7.

GCF(42,49) = 7

We will now calculate the prime factors of 42 and 49, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 42 and 49.

GCF Calculator and
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## How to find the GCF of 42 and 49?

We will first find the prime factorization of 42 and 49. After we will calculate the factors of 42 and 49 and find the biggest common factor number .

### Step-1: Prime Factorization of 42

Prime factors of 42 are 2, 3, 7. Prime factorization of 42 in exponential form is:

42 = 21 × 31 × 71

### Step-2: Prime Factorization of 49

Prime factors of 49 are 7. Prime factorization of 49 in exponential form is:

49 = 72

### Step-3: Factors of 42

List of positive integer factors of 42 that divides 42 without a remainder.

1, 2, 3, 6, 7, 14, 21

### Step-4: Factors of 49

List of positive integer factors of 49 that divides 42 without a remainder.

1, 7

#### Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 42 and 49. The biggest common factor number is the GCF number.
So the greatest common factor 42 and 49 is 7.

Also check out the Least Common Multiple of 42 and 49