Adding Fractions with unlike denominators


The math learning center is an app and online platform that allows students to use manipulatives virtually. In this activity, students will use virtual manipulatives to add fractions.


Students will:

  • Be able to make two fraction addition problems using The Math Learning Center App.


Vocabulary Words:

  1. Fraction: A fraction is a part of a whole. A common fraction is made up of a numerator and a denominator. The numerator is shown on top of a line and is the number of parts of the whole. The denominator is shown below the line and is the number of parts by which the whole has been divided.


To prepare for this lesson:

  • Teachers will need to have the app or website for virtual manipulatives available to students.

Note: The Math Learning Center has many free apps available for teachers and students. For more information, visit the Math Learning Center.


See Accommodations Page and Charts on the site in the Teacher Resources.


Directions for this activity:

  1. Teach students about fractions as parts of a whole. Students should have some prior knowledge of fractions.
  2. Show video:
  3. Practice together:  Math Learning Center.
  1. Explain to students that when adding fractions, they have to have equivalent parts. For example, if a fraction’s denominator is 12, the fraction it’s added with must also have 12 as the denominator, thus have a common denominator.
  2. To make denominators common, you can divide the larger denominator by the smaller and get a multiple.
  3. You must multiply the denominator and numerator to make the fractions have common denominators.

  4. numerous fractions

  5. As you show how to create a common denominator to add fractions, have students help you figure out the multiple.
  6. Use the annotate feature to label each math sentence.
  1. Video 2:
  2. Practice Together:
  1. Practice together:  Math Learning Center.
  1. Video 3:
  2. Practice:

Note: Early finishers may screenshot their work and save it to their computer or upload to an electronic portfolio like SeeSaw.


Different options for assessing the students:

This was modified from MiTechKids activity:  adding fractions

Remixed with resources from Khan Academy and ck-12

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