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Worksheet
Curated OER

Greatest Common Divisor

For Students 9th - 10th
In this greatest common divisor worksheet, students use prime factorization to determine the greatest common factors of two or more numbers. Explanations and examples are provided. This two-page worksheet contains ten problems.
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Lesson Plan
Curated OER

Euclidean Algorithm

For Teachers 9th - 12th
Students are introduced to the concept of a Greatest Common Divisor. They review the number systems. Students are told how the entire field of Number Theory primarily uses the integers. They are told the Fundamental Theorem of Algebra.
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Worksheet
Curated OER

Greatest Common Divisor

For Students 5th - 6th
In this math worksheet, students learn to find the greatest common divisor of two numbers. Students read and study the information and examples before solving 10 problems.
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Unknown Type
Amby Duncan-Carr

Greatest Common Factor/online Lesson

For Students 9th - 10th
A complete lesson on Greatest Common Factors, including methods of finding, examples, and a practice multiple-choice quiz.
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Activity
University of Regina (Canada)

University of Regina: Math Central: Greatest Common Divisor and Least Common Multiple

For Students 9th - 10th
Learn about the greatest common divisor, the least common multiple, and the Euclidean Algorithm. This resource gives a description of each of these concepts, accompanied by several examples.
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Unknown Type
University of Waterloo (Canada)

University of Waterloo: Cemc: Math Circles: Number Theory Ii [Pdf]

For Teachers 9th - 10th
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.
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Activity
Amby Duncan-Carr

Amby Duncan Carr: Amby's Math Resources

For Students 9th - 10th Standards
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.
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Lesson Plan
George Mason University

Margo Mankus: Investigating Lcm and Gcf Using Rods

For Teachers 9th - 10th Standards
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.
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Activity
Wolfram Research

Wolfram Math World: Greatest Common Divisors

For Students 9th - 10th
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.
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Activity
Texas Instruments

Texas Instruments: Gcd and Lcm

For Teachers 9th - 10th
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.
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Activity
Purple Math

Purplemath: Lcm & Gcf

For Students 9th - 10th Standards
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.
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Interactive
Other

Greatest Common Factor Calculator

For Students 9th - 10th Standards
Free online calculator provides help with finding the greatest common factor.
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Interactive
Calculator Soup

Calculator Soup: Greatest Common Factor Gcf Calculator

For Students 6th - 8th Standards
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.
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Handout
Cuemath

Cuemath: Highest Common Factor

For Students 9th - 10th Standards
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...
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Handout
Wolfram Research

Wolfram Math World: Euclid's Algorithm

For Students 9th - 10th
This site from Mathworld.com provides a very detailed description of Euclid's algorithm of common divisors and a method of finding the greatest.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Greatest Common Factors, Least Common Multiples

For Students 9th - 10th
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.
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Unknown Type
Math Slice

Math Slice: Greatest Common Divisor (Factor): Math Worksheets

For Students 3rd - 5th Standards
This tool allows you to create worksheets where students must find the greatest common factor in a set of two to four whole numbers.