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CK-12 Foundation
Ck 12: Elem Math: Finding the Least Common Denominator
[Free Registration/Login may be required to access all resource tools.] In this learning module, students must find the least common denominator for the fractions they are presented with. Includes video demonstrating a sample problem...
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: Least Common Denominator
Find a quick, concise explanation of how to find the least common denominator for fractions or rational expressions. Examples are given and clearly explained.
Other
Help With Fractions: Least Common Denominator
The rules for finding the least common denominator are clearly explained at this website. Two different methods are given. This is an excellent place to get step by step explanations for working with fractions.
Calculator Soup
Calculator Soup: Lcd Calculator Least Common Denominator
Use this Least Common Denominator Calculator to find the lowest common denominator (LCD) of fractions, integers and mixed numbers. Finding the LCD is important because fractions need to have the same denominator when you are doing...
Homeschool Math
Homeschool Math: Finding the (Least) Common Denominator
Students learn about finding a common denominator in fraction addition and subtraction.
CK-12 Foundation
Ck 12: Elem Math: Subtracting Fractions With Different Denominators
[Free Registration/Login may be required to access all resource tools.] In this learning module, students must find the least common denominator of two fractions in order to subtract one from the other. Includes video demonstrating a...
Khan Academy
Khan Academy: Common Denominators
In this exercise, students practice finding common denominators. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.
ClassFlow
Class Flow: Finding the Common Denominator
[Free Registration/Login Required] This flipchart presents a method for finding the common denominator of fractions.
Illustrative Mathematics
Illustrative Mathematics: Finding Common Denominators to Add
Part (a) of this task asks learners to find and use two different common denominators to add the given fractions. The purpose of this question is to help students realize that they can use any common denominator to find a solution, not...
Illustrative Mathematics
Illustrative Mathematics: Finding Common Denominators to Subtract
Part (a) of this task asks students to use two different denominators to subtract fractions. The purpose of this is to help students realize that any common denominator will work, not just the least common denominator. Part (b) does not...
Other
Active Maths Limited: Adding & Subtracting Fractions: Whiteboard Resources
This is an excellent resource to visually illustrate adding and subtracting fractions by finding the lowest common denominator.
AAA Math
Aaa Math: Least Common Denominator
This site explains how to find the least common denominator. Also provides games to work on this skill.
Better Lesson
Better Lesson: Finding the Least Common Multiple (Lcm)
The LCM is a useful tool to use when comparing fractions and finding common denominators.
CK-12 Foundation
Ck 12: Arithmetic: Sums of Fractions With Different Denominators
[Free Registration/Login may be required to access all resource tools.] In this lesson students find sums of fractions with different denominators by renaming them with common denominators. Students examine guided notes, review guided...
AAA Math
Aaa Math: Adding Fractions With Different Denominators
This personal site explains how to add fractions with different denominators by finding the least common denominator. Gives problems and games to practice this skill.
Scholastic
Scholastic Math Maven's Mysteries: The Mystery of Pirate Ringold's Lost Treasure
In this Math Maven mystery, read the legend of Pirate Ringold and his treasure and help Frieda Finditall figure out how much gold there is left to find on this old ship. Your knowledge about addition and subtraction with fractions will...
Sophia Learning
Sophia: Addition and Subtraction of Rational Expressions
Use the examples to find the least common denominator in order to add and subtract rational expressions.
Oswego City School District
Regents Exam Prep Center: Add and Subtract Rational (Fractional) Expressions
Add and subtract rational expressions like a pro after you use this site. Finding common denominators is made easy with this tutorial. Try the example problems to test your knowledge, then check the solutions. The 'Topic Index' page...
CK-12 Foundation
Ck 12: Arithmetic: Differences of Fractions
[Free Registration/Login may be required to access all resource tools.] Find differences of fractions with different denominators by renaming them with a common denominator.
Other
Mr. Perez Online Math Tutor: Solving Rational Equations
The mathematics tutorial investigates how to simplify rational equations, find the least common denominator as well as how to solve rational equations. There are notes, examples and an interactive applet as well as a vocabulary puzzle.
Lawrence Hall of Science
The Math Page: Skill in Algebra: Equations With Fractions
Here is a site that clearly and thoroughly explains solving equations with fractions by finding the least common multiple of the denominators and clearing the fractions. There are example problems solved, problems for the student to...