Greatest Common Factor of 20 and 643

GCF(20, 643) = 1, Greatest common factor of 20 and 643 is 1. Greatest Common Factor or Greatest Common Divisor of two numbers is the largest integer by which both the numbers can be divided. There are two different methods to calculate Greatest Common Factor of 20 and 643. Greatest Common Factor by prime factorization method and Greatest Common Factor by matching factors method.

Greatest Common Factor of 20 and 643 by prime factorization method

We will first find the prime factorization of 20 and 643.
Prime Factorization of 20 is 1, 2, 2, 5 and Prime Factorization of 643 is 1, 643.

  • Factorize\( (20) = \) \(1\times 2\times 2\times 5\)
  • Factorize\( (643) = \) \(1\times 643\)
Now we need to find any which are common for each number (1, 1) and multiply these numbers together.
\(GCF(20, 643) = 1\times 1 = 1\).

Greatest Common Factor of 20 and 643 by matching factors method

List of positive integers factors of 20 leaving a remainder zero is 1, 2, 4, 5, 10, 20
List of positive integers factors of 643 leaving a remainder zero is 1, 643
As you can see, 1 is the greatest and common number that 20 and 643 divides into.
So the greatest common factor 20 and 643 is 1.
\(GCF(20, 643) = 1\).

If you want to learn more about greatest common divisor, take a look at the Wikipedia page.
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