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Greatest Common Factor Calculator
Free online calculator provides help with finding the greatest common factor.
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.
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.
![University of Waterloo: Cemc: Math Circles: Number Theory Ii [Pdf] Unknown Type](https://d15y2dacu3jp90.cloudfront.net/images/attachment_defaults/resource/large/FPO-knovation.png "University of Waterloo: Cemc: Math Circles: Number Theory Ii [Pdf] Unknown Type")
University of Waterloo (Canada)
University of Waterloo: Cemc: Math Circles: Number Theory Ii [Pdf]
This worksheet provides a series of problem-solving questions that require higher order thinking skills. Questions will include finding the greatest common divisor, and least common multiple.
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.
Math Slice
Math Slice: Greatest Common Divisor (Factor): Math Worksheets
This tool allows you to create worksheets where students must find the greatest common factor in a set of two to four whole numbers.
Calculator Soup
Calculator Soup: Greatest Common Factor Gcf Calculator
Calculate GCF, GCD, and HCF of a set of two or more numbers and see the work using factorization. An interactive calculator, explanations, and examples are included.
Mathigon
Mathigon: Math Foundations: Divisibility and Prime: Greatest Common Factors
This lesson focuses on the greatest common factors it poses real situations and asks students answer them and then it provides more information and more exercises.
Texas Instruments
Texas Instruments: Gcd and Lcm
In this activity students use the Computer Algebra System CAS tool to compute greatest common divisor (GCD) and least common multiple (LCM) of numbers and expressions.
Cuemath
Cuemath: Highest Common Factor
Explore the world of Highest Common Factor or Greatest Common Factor (GCF) by going through its various aspects and properties. Find answers to questions like what is the highest common factor for a group of numbers, easy ways to...
Math Slice
Math Slice: Greatest Common Divisor (Factor)
This resource allows students to practice finding the greatest common factor among 2, 3, or 4 numbers. Students are able to select parameters of how many numbers they will compare, and the range of possible numbers. There are ten...
Khan Academy
Khan Academy: Gcf & Lcm Word Problems
Solve word problems where you either need to find the GCF or LCM. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Khan Academy
Khan Academy: Greatest Common Factor
Find the greatest common factor of 2 or 3 integers. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
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.
Elias Saab
Math Drills: Lcm and Gcd Quiz
An interactive quiz which provides students with two numbers and asks them to find either the Least Common Multiple or the Greatest Common Divisor between them. Students input their solution and have the program evaluate it. Hints are...
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.
Calculator Soup
Calculator Soup: Common Factors Calculator
This calculator factors a set of positive integers to find the common factors (common divisors) of those integers. Enter the set of numbers you want to factor separating them with commas.
University of Vienna (Austria)
University of Vienna: Elementary Properties of Numbers
Quick interactive assessment which determines skill level on fraction equivalence, prime factorization, and common divisors/multiples.
Wolfram Research
Wolfram Math World: Euclid's Algorithm
This site from Mathworld.com provides a very detailed description of Euclid's algorithm of common divisors and a method of finding the greatest.