What is greatest common factor of 15 and 20

General
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what is greatest common factor of 15 and 20

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What is the greatest common factor of 15 and 20?

Answer: The greatest common factor (GCF), also known as the greatest common divisor (GCD), of two numbers is the largest number that evenly divides both of them. To find the GCF of 15 and 20, we can follow these steps:

1. List the factors of each number:

  • Factors of 15: 1, 3, 5, 15
  • Factors of 20: 1, 2, 4, 5, 10, 20

2. Identify the common factors:

  • The common factors of 15 and 20 are 1 and 5.

3. Determine the greatest common factor:

  • The greatest common factor among these is 5.

Therefore, the greatest common factor (GCF) of 15 and 20 is 5.

This method ensures accuracy by breaking down the process of identifying common factors. Alternatively, you can use the prime factorization method:

Prime Factorization Method:

  • Prime factorization of 15: 15 = 3 \times 5
  • Prime factorization of 20: 20 = 2^2 \times 5

The only common prime factor is 5. Thus, the GCF is 5.

Whichever method you use, the greatest common factor of 15 and 20 remains 5.