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What is the Greatest Common Factor of 9 and 42?

Greatest common factor (GCF) of 9 and 42 is 3.

GCF(9,42) = 3

We will now calculate the prime factors of 9 and 42, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 9 and 42.

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How to find the GCF of 9 and 42?

We will first find the prime factorization of 9 and 42. After we will calculate the factors of 9 and 42 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 42

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

42 = 21 × 31 × 71

Step-3: Factors of 9

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

1, 3

Step-4: Factors of 42

List of positive integer factors of 42 that divides 9 without a remainder.

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

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 9 and 42. The biggest common factor number is the GCF number.
So the greatest common factor 9 and 42 is 3.

Also check out the Least Common Multiple of 9 and 42