Learn Greatest Common Factor

Introduction:
        Greatest Common Factor (GCF) is the greatest number that is a factor of each of two or more numbers. To find either the Least Common Multiple (LCM) or Greatest Common Factor (GCF) of two numbers, you always start out the same way: you find the prime factorizations of the two numbers. Then you put the factors into a nice neat grid of rows and columns, and compare and contrast and take what you need.
Let us study the GCF of two numbers 24 and 15.
The factors of 24 are 1,2,3,4,6,8,12 and 24.
The factors of 15 are 1,3,5 and 15.
From this we observe that the greatest factor common to both these numbers are 3. In other words we can say that the greatest common factor of 24 and 15 is 3.

Greatest Common Factor Learning

Another method of finding out  the GCF is by using prime factorisation. The prime factors of 8 are 1,2,2,2 and that of 12 are 1,2,2,3. The prime factors that is  common for both numbers are 1,2,2. Multiply together all these numbers and we get 4. We can say that 4 is the greatest common factor of these numbers.