Common Denominators

Contributor: Elephango Editors. Lesson ID: 10628

Do you love fractions? Or do they send you running for the hills? Complete these low-stress online activities to discover fractions aren't that hard after all. You'll even get to play fun games!


Fractions and Operations

learning style
Auditory, Visual
personality style
Grade Level
Intermediate (3-5)
Lesson Type
Quick Query

Lesson Plan - Get It!


Do you break out into a cold sweat when your teacher talks about adding and subtracting fractions? If you do, then this is the right lesson for you!

Adding and subtracting fractions may get your heart racing, but there is nothing to fear!

You will learn how to add and subtract fractions that have a common denominator. Common denominator just means that the two fractions you are adding or subtracting have the same exact denominator.

By the end of this lesson, you will love adding and subtracting fractions!

Let's imagine you have a garden in your backyard. Every spring, tulips and daffodils begin to pop up out of the ground.

On a sunny spring day, you go outside with a ruler to measure how tall the new plants have grown so far. The tulips are 7/16 inches out of the ground. The daffodils are only 3/16 out of the ground:

tulips and daffodils

  • How many inches have the tulips and the daffodils grown in total?

To solve this problem, we will add the fractions.

Since both fractions share a common denominator, you are ready to add!

add common denominators

First, make sure our addition problem is lined up correctly. The numerators need to be in line horizontally, and the denominators need to be in line horizontally:


Now, simply add the numerators. Next, put that number as the numerator in the answer:

solve for the numerator

Finally, since you have common denominators, just move over the same denominator to your answer:

slide over the denominator

Great! The flowers have grown 10/16 inches in total!

Before we move on, let's check to make sure our answer is in simplest form.

To review simplest form, go through the Study Jams! Step By Step for Simplest Form.

To make 10/16 into simplest form, we will divide the numerator and denominator by 2.

simplest form

So, the flowers have grown 5/8 inches in total!

Now, you are ready for some practice! Visit the Got It? section to show off your skills.

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