What is the greatest common factor of 21 and 306?

Answer 1

The greatest common factor (GCF) of 21 and 306 is 3. To find the GCF, you need to identify the factors of each number. The factors of 21 are 1, 3, 7, and 21, while the factors of 306 are 1, 2, 3, 6, 9, 17, 18, 34, 51, 102, 153, and 306. The largest number that both 21 and 306 share as a factor is 3, making it the greatest common factor.

Answer 2

The GCF of 21 and 306 is 3.

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

The factors of 21 are 1, 3, 7, and 21.

The factors of 306 are 1, 2, 3, 6, 9, 17, 18, 34, 51, 102, 153, and 306.

The common factors are 1 and 3. Therefore, the greatest common factor is 3.

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

The prime factors of 21 are 3 and 7.

The prime factors of 306 are 2, 3, 3, and 17.

The prime factors in common are a single 3, so the greatest common factor is 3.

Answer 3

GCF of 21 and 306 is 3.