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.
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...
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.
Better Lesson
Better Lesson: Multiples, Lcm, and Gcf
What are multiples? How do they compare with factors? Students work to answer these questions and develop an understanding of greatest common factor and least common multiple.
Better Lesson
Better Lesson: Greatest Common Factor & Least Common Multiple
Clearly understand the difference between factors and multiples builds a foundation for applications and problem solving using GCF and LCM.
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.
Mangahigh
Mangahigh: Number: Least Common Multiple and Greatest Common Factor
This site provides students practice with the concept of least common multiples and greatest common factors. Students can learn about the topic by completing an interactive tutorial. Students can then take a ten question timed test to...
McGraw Hill
Glencoe: Self Check Chapter Test Fractions and Decimals
Students are assessed on fractions and decimals. Topics include greatest common factor, improper fractions, and fractions as decimals. The self-checking test includes hints and solutions.
Doina Popovici
Math Play: Factors and Multiples Game
A jeopardy style game that students can play with others or alone to practice their skills at identifying multiples and factors.
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.
Cool Math
Coolmath: Gcf's and Lcm's Common Multiples
These prealgebra-arithmetic lessons explain greatest common factors (GCF's) and least common multiples (LCM's) and show how to find them.
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.
Shmoop University
Shmoop: Basic Operations: Lcm & Gcf
Students learn about the least common multiple and the greatest common factor. The resource consists of notes, step-by-step examples, and practice problems with solutions.
Goodwill
Gcf Global: Reciprocals and Inverse Numbers
Read this tutorial to learn about reciprocal and inverse numbers and how they work.
Khan Academy
Khan Academy: Factor With the Distributive Property
Practice applying the distributive property to factor numerical expressions (no variables). Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
That Quiz
That Quiz: Factores
Interactive practice tests dealing with factors. Students will practice the prime factors, greatest common factor and least common multiple.
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.
Texas Instruments
Texas Instruments: Oliver's Method
Students discover a relationship between the Greatest Common Factor (GCF) and the Least Common Multiple (LCM) of two numbers. Students will find and justify the relationship that the product of two numbers is equal to the product of the...
Goodwill
Gcf Global: Sharing and Collaborating on Files
Google Drive makes sharing files simple. It also allows multiple people to edit the same file, allowing for real-time collaboration. Watch a video to learn more about these features. Includes examples and exercises. [2:58]
Better Lesson
Better Lesson: Lcm Stations Activity
Learning about factors and multiples allows students to see number relationships and apply those number relationships to multiplication and division.
Goodwill
Gcf Global: Basic Skills
Intimidated by computers? New to email and the Internet? Curious about operating systems and online safety? We've got the information you need to better understand computers and how they work. This is a landing page that has multiple...
Topmarks Online
Topmarks: Multiples and Factors
A multiple-choice game with two game modes. In the first, you need to identify the Lowest Common Multiple and in the second the Highest Common Factor. Questions increase in difficulty depending on accuracy.
Varsity Tutors
Varsity Tutors: Hotmath: Graphing Calculator Practice Problems Number Theory
Practice using your graphing calculator for number theory problems, including prime factorization, greatest common factor, least common multiple, and scientific notation. If you get stumped or if you would like to check your work, then...
Cuemath
Cuemath: Least Common Multiple
Learn about the properties of Least Common Multiples (LCM) and the three methods to find the LCM. Included are solved examples and interactive problems for review.