Brick Math
  • Home
  • Curriculum
    • For Schools
    • For Teachers
    • For Parents/Homeschool
  • Order
    • Products
    • School Orders
    • International Orders
  • Videos
  • Praise
  • Blog
  • About
    • Sample Lessons
    • Summer Programs
    • FAQ
  • Contact
    • Lesson of the Month
Picture
Picture

The Fraction train - Adding fractions with unlike denominators using Lego bricks

3/15/2018

0 Comments

 
​Teaching students to add fractions that have unlike denominators can be a challenge. It starts with teaching how to find a common denominator. Far too often, this can lead to a purely procedural account of the how, but not the why behind the math. Using LEGO bricks to teach this concept brings new understanding of the term “common denominator” by providing a visual and tactile link.
 
A key piece of knowledge when comparing fractions concerns understanding same-sized wholes. Students often make errors when trying to add or subtract fractions because they don’t grasp the concept that fractions can only be compared if the whole (the denominator) for both fractions is the same size.
 
Let’s add the fractions 1/4 and 1/3 together to show how the process works. First, build models of the two fractions on a baseplate using LEGO bricks. Model the fraction 1/4 with a 1x1 brick and a 1x4 brick, placing the 1x1 brick above the 1x4 brick.  Model the fraction 1/3 with a 1x1 brick and a 1x3 brick in the same way. Build the 1/3 fraction model next to the 1/4 fraction model, leaving a little space between them, as shown.
Picture
​In algebra, we use the phrase, “What you do to the left you must do to the right,” to help remember how to approach equations. Here we say, “What you do to the bottom you must do to the top,” to remember that the way you treat the denominator defines the way you treat the numerator. The fraction train shows the multiplication that takes place as you build the common denominator model. Note: As you build the fraction train, you distinguish between counting bricks and counting studs.
 
To build the fraction train, find another 1x4 brick and place it on the baseplate below the two fraction models. Then find another 1x3 brick and place it just underneath the 1x4 brick. 
Picture
This begins the fraction train and represents the two fractions in the order they appear in the equation: 1/4 + 1/3 = ____. Add another 1x4 brick to the train, and then another 1x3 brick to its train. Continue adding 1x4 bricks to that train and 1x3 bricks to the other train until both fraction trains of bricks are the same length. Ask students to count the number of studs in each line when they are equal in length. (Answer: 12.)
Picture
​This is the common denominator. Place a 1x12 brick at the bottom of the baseplate to represent the common denominator of 12. This is part of the solution model. 

​Now it’s time to determine the numerators, based on the common denominator. Start with the 1/4 fraction. Look at the fraction train built by the 1x4 bricks and ask: “How many 1x4 bricks are in the train?” (Answer: there are 3.) Now look at the model of the fraction 1/4 and ask: “What brick represents the numerator of the fraction 1/4? (Answer: the 1x1 brick.) Remind students that what you do to the bottom you must do to the top. Since there are three 1x4 bricks in the denominator, there must be three 1x1 bricks in the numerator of the solution. Place three 1x1 bricks above the 1x12 brick that represents the common denominator in the solution.
 
Repeat the process for the fraction 1/3 by counting the number of 1x3 bricks in the fraction train. (Answer: there are 4.) Since there are four bricks, place four 1x1 bricks in the solution model next to the three 1x1 bricks you just added. 
Picture
​Count the number of studs in the numerator: 7
Count the number of studs in the denominator: 12
The solution: 1/4  + 1/3 = 3/12 + 4/12 = 7/12

When you take students through the modeling of the solutions, you give them a powerful way to visualize what common denominators look like. Creating and modeling same-sized wholes (the fraction train that shows the common denominator) with LEGO bricks is key to understanding how to add unlike fractions. For both visual and tactile learners, this method helps students understand the multiplication process utilized with fractions, as well as the relationship of same-sized wholes and common denominators.

​If you want to learn more about how to teach using LEGO bricks, check the website for the Brick Math program, www.brickmath.com. 
0 Comments

Your comment will be posted after it is approved.


Leave a Reply.

    Categories

    All
    7th 8th Grades
    7th-8th Grades
    Addition
    Advanced Measurement
    Brick Math Series
    Brick Sets
    Counting
    COVID
    Data And Statistics
    Decimals
    Differentiation
    Division
    Fractions
    Gifted Students
    Grants
    Homeschooling
    Learning Math
    Lesson Of The Month
    Measurement
    Multiplication
    News
    Play
    Pre Algebra
    Pre-Algebra
    Research
    School Districts
    Shirley Disseler
    Subtraction
    Summer School
    Survey
    Videos
    Year Of Brick Math

    Archives

    April 2025
    March 2025
    February 2025
    January 2025
    December 2024
    October 2024
    September 2024
    August 2024
    July 2024
    June 2024
    May 2024
    April 2024
    March 2024
    February 2024
    January 2024
    December 2023
    November 2023
    October 2023
    September 2023
    August 2023
    July 2023
    June 2023
    May 2023
    April 2023
    March 2023
    February 2023
    January 2023
    December 2022
    October 2022
    August 2022
    June 2022
    May 2022
    April 2022
    February 2022
    January 2022
    December 2021
    November 2021
    October 2021
    September 2021
    August 2021
    July 2021
    June 2021
    May 2021
    April 2021
    March 2021
    February 2021
    January 2021
    December 2020
    November 2020
    October 2020
    September 2020
    August 2020
    July 2020
    June 2020
    May 2020
    April 2020
    March 2020
    February 2020
    January 2020
    December 2019
    November 2019
    September 2019
    August 2019
    July 2019
    June 2019
    March 2019
    January 2019
    November 2018
    October 2018
    April 2018
    March 2018
    February 2018
    December 2017
    November 2017
    September 2017
    July 2017
    May 2017
    April 2017
    March 2017
    January 2017
    December 2016
    October 2016

Shop Online
​

Learn  More
Company

SCHOOL ORDERS

​TEACHER OrderS

PARENTS/HOMESCHOOL ORDERS

INTERNATIONAL ORDERS
CURRICULUM FOR SCHOOLS
CURRICULUM FOR TEACHERS
CURRICULUM FOR PARENTS/HOMESCHOOL
STUDIES
DIFFERENTIATION
RESEARCH
TRACKING
ALIGNMENT

About

BLOG

FAQ

Contact

Brick Math  |  211 North Ave.  |  St. Johnsbury  |  Vermont  |  05819   
P 802-751-8802  |  F 802-751-8804
Terms of Use 
 |  Privacy Policy  |  Copyright © Brick Math 2025
Partial funding for development of this website made possible by a Rural Business Development Grant through the Northern Community Investment Corporation from USDA Rural Development.
  • Home
  • Curriculum
    • For Schools
    • For Teachers
    • For Parents/Homeschool
  • Order
    • Products
    • School Orders
    • International Orders
  • Videos
  • Praise
  • Blog
  • About
    • Sample Lessons
    • Summer Programs
    • FAQ
  • Contact
    • Lesson of the Month