Amby Duncan-Carr
Greatest Common Factor/online Lesson
A complete lesson on Greatest Common Factors, including methods of finding, examples, and a practice multiple-choice quiz.
Amby Duncan-Carr
Amby Duncan Carr: Amby's Math Resources
Amby's Math Resources site is a tutorial that explains finding the greatest common factor. It also has examples that are done for you step by step, as well as examples for you to try (and check) on your own.
George Mason University
Margo Mankus: Investigating Lcm and Gcf Using Rods
This lesson plan is for an activity using rods (Cuisenaire Bars) to help students understand the concept of factors, in particular the LCM and GCF of two numbers.
Wolfram Research
Wolfram Math World: Greatest Common Divisors
An advanced investigation of Greatest Common Factors (Divisors) and a look at related algorithms and properties) comutative, associative, and more). Contains links to relevant topics.
Texas A&M University
Wtamu Virtual Math Lab: Intermediate Algebra: Gcf and Factoring by Grouping
Excellent tutorial on GCF of polynomials, including examples and step-by-step instruction on factoring.
Math.com
Math.com: Greatest Common Factor/practice Calculator
A page which generates number pairs and allows the user to find and enter the GCF. Keeps a running tally of correct/incorrect answers and has links to in depth review, if needed.
Discovery Education
Discovery Education: Web Math: Greatest Common Factor
This WebMath site contains a tool for locating the greatest common factor. Simply plug in the numbers and you are on your way! Use it to check your answers.
Other
Help With Fractions: The Greatest Common Factor
Two different methods of finding the greatest common factor are explained at this one page website. It is very easy to follow the step by step directions.
Discovery Education
Discovery Education: Web Math: Factoring Polynomials by Finding the Gcf
This WebMath online tool is useful for factoring polynomials by finding the greatest common factor. Simply plug the numbers in and you are on your way!
Purple Math
Purplemath: Lcm & Gcf
Purplemath shows an easy and orderly way to determine the GCF and LCM of any two numbers. Even large numbers won't be a challenge with this method.
AAA Math
Aaa Math: Practice Finding Greatest Common Factor
This lesson contains a learning exercise in which the user has to find the greatest common factor and type it in. The exercise keeps track of how many right and wrong answers given and gives you a grade.
University of Georgia
University of Georgia: Greatest Common Factor
This is geared to teachers with the objective of helping students use their TI-34 calculators to find the greatest common factor. Includes working examples.
National Council of Teachers of Mathematics
The Math Forum: Learning to Factor
Math Forum Faq which briefly defines greatest common factor and links to an in-depth investigation of how the GCF is found.
National Council of Teachers of Mathematics
The Math Forum: Finding the Greatest Common Factor of Two Numbers
Math Forum response to question about finding the greatest common factor by using the factoring tree method.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Formula for Greatest Common Divisor.
This site is a question and response to a student asking Dr. Math about the greatest common divisor, he gives an interesting way to find the gcd, as well as the button on calculators which commonly does the math for you.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Greatest Common Factors, Least Common Multiples
Math Forum response to request for info on how to find greatest common factors, and how this compares to least common multiples. Explanation includes examples of each.
Other
Locating the Greatest Common Factor
This site provides a detailed example of how to locate the greatest common factor. Is useful for students who need additional help in learning to find the greatest common factor.
Other
Greatest Common Factor/definition and Example
A walkthrough example of the discovery of the GCF of three numbers. Contains a definition as well.
Other
Greatest Common Factor/example
An example (with full explanation) where a Greatest Common Factor is found.