What is the greatest common factor of 9 and 20?

Answer 1

The GCF of 9 and 20 is 1.

One way to determine the greatest common factor is to find all the factors of the numbers and compare them.

The factors of 9 are 1, 3, and 9.

The factors of 20 are 1, 2, 4, 5, 10, and 20.

The only common factor is 1. Therefore, the greatest common factor is 1, which means the numbers are relatively prime.

The greatest common factor can also be calculated by identifying the common prime factors and multiplying them together.

The prime factors of 9 are 3 and 3.

The prime factors of 20 are 2, 2, and 5.

There are no prime factors in common, so the numbers are relatively prime, which means the greatest common factor is 1.

Another way to approach this is to look at the difference between 9 and 20, which is 11. The greatest common factor of two numbers cannot be larger than the difference between the two numbers and must be a factor of the difference. Since 11 is a prime number, the greatest common factor must be either 1 or 11. The numbers 9 and 20 are not divisible by 11, so the greatest common factor must be 1.

Answer 2

your answer is 1