## About Greatest Common Factor (GCF):

The Greatest Common Factor (GCF), also known as the Greatest Common Divisor (GCD), is the largest positive integer that divides each of a set of integers without leaving a remainder. It is used to find the highest common factor of two or more numbers.

Here are some examples to help illustrate the concept:

- The GCF of 12 and 16 is 4. This is because 4 is the largest number that divides both 12 and 16 without leaving a remainder.
- The GCF of 18 and 24 is 6. This is because 6 is the largest number that divides both 18 and 24 without leaving a remainder.
- The GCF of 15 and 25 is 5. This is because 5 is the largest number that divides both 15 and 25 without leaving a remainder.

In order to find the GCF of more than two numbers, it is helpful to use the Euclidean algorithm. This algorithm is based on the fact that the GCF of two numbers is the same as the GCF of the smaller number and the remainder of the larger number divided by the smaller number. The process is then repeated until the remainder is zero, at which point the smaller number is the GCF of the two original numbers.

For example, to find the GCF of 12, 16, and 20:

- First, divide 20 by 16: 20 % 16 = 4
- Next, divide 16 by 4: 16 % 4 = 0
- Since the remainder is zero, 4 is the GCF of 12, 16, and 20.

In general, the GCF is a very useful tool when you want to simplify fractions, find the least common multiple (LCM) of numbers, or when you need to factorize polynomials.