Greatest common factor

Fortunately, a number of shortcut rules exist for determining this and it is not always necessary to perform long-hand calculations.

So a divisor and a factor are kind of the same thing. Find the GCF of and We will continue to divide until we have two numbers that are relatively prime.

Notice that the mark on the first gear returns to its original position after each full revolution. This is the sign that the factor tree is complete. GCF is helpful in problem solving as well. Subtract the result from Step 2 from the new larger number. When we see key words like largest, greatest and most combined with questions about breaking things into groups we know that we are solving a GCF question.

The number k is the Greatest Common Factor of 20 and The question asked how many revolutions are needed to realign the mark. The factors of 27 are 1, 3, 9, And that's really not so special.

What is the greatest number of children she can give candy? And that makes a lot of sense because 6 actually is divisible into And I'll throw out some terminology here for you. Hopefully you're ready to do the greatest common divisor or factor problems. I know 12's coming up a lot. So just to be clear, first of all, when someone asks you whether what's the greatest common divisor of 12 and 8?

So the largest number we can divide both 12 and 30 exactly by is 6, like this: So in this situation the greatest common divisor-- and I apologize that I keep switching between divisor and factor.

Find the GCF of 18 and 27 The factors of 18 are 1, 2, 3, 6, 9, Pick out the largest factor that both lists have in common and call this the GCF.

Include only the factors common to all three numbers. So we're not just interested in finding a common factor, we're interested in finding the greatest common factor.Calculate the GCF, GCD or HCF and see work with steps.

Find the greatest common factor using factoring, prime factorization and the Euclidean Algorithm. The greatest common factor of two or more whole numbers is the largest whole number that divides evenly into each of the numbers.

Greatest Common Factors. The largest common factor of two numbers is called their greatest common factor or highest common factor. Example: What is the greatest common factor of 20 and 25?

The common factors of 20 and 25 are 1 and 5. (see above) The greatest common factor is 5. Greatest Common Factor Short description: Learn how to find the greatest common factor of two numbers and how this can be used to solve problems with large numbers in this Math Shorts video.

Long description: In this video, learn how to find the greatest common factor of two numbers.  