Adding and Subtracting Fractions: Same Denominator

Contributor: Erika Wargo. Lesson ID: 12535

You have two hours before bed. You have to practice piano for a quarter of the time, then do homework for two quarters of the time. How much time do you have left for TV? Take time to learn fractions!

categories

Elementary

subject
Math
learning style
Visual
personality style
Otter
Grade Level
Intermediate (3-5)
Lesson Type
Skill Sharpener

Lesson Plan - Get It!

Audio:

The pizza you are eating for dinner has 8 slices. You ate 28 of the pizza. Your brother ate 58 of the pizza. How much of the pizza did you and your brother eat? How much more pizza did your brother eat than you?

Fractions are numbers less than 1 that show part of a whole.

The top number of a fraction is the numerator. The bottom number of a fraction is the denominator. Fractions with the same denominator have common denominators.

Watch a short video to review adding and subtracting fractions with the same denominator and write down the answers to these questions:

  • When adding or subtracting fractions with the same denominator, which numbers do we add?
  • When adding or subtracting fractions with the same denominator, which numbers stay the same?
  • Does subtracting fractions work the same way as adding fractions?

Discuss the questions above after you have watched Math Antics - Adding and Subtracting Fractions:

 

Example 1

 5  +  3  =  
19 19  

When fractions have a common denominator, add the numerators and keep the denominator the same:

 5  +  3  =  8 
19 19 19

Example 2

 15  +  12  =  
20 20  

When fractions have a common denominator, subtract the numerators and keep the denominator the same. Be sure to subtract the smaller number from the larger number:

 15  +  12  =  3 
20 20 20

Now, you will move on to the Got It? section to complete interactive practice with adding and subtracting fractions.

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