Back To Course

Math for Kids23 chapters | 325 lessons

{{courseNav.course.topics.length}} chapters | {{courseNav.course.mDynamicIntFields.lessonCount}} lessons | {{course.flashcardSetCount}} flashcard set{{course.flashcardSetCoun > 1 ? 's' : ''}}

Instructor:
*Sarah Palacios*

Sarah has completed her master’s degree in Education from the University of Texas and has received her bachelors in Interdisciplinary Studies specializing in Mathematics. She graduated with honors, Magna cum Laude, from Texas A&M University. She currently holds a principal certificate, a teaching certificate for Mathematics grades 4-8, a teaching certificate for EC – 6 as a generalist, as well as an ESL certificate. She has been an elementary school teacher for the past 4 years and is passionate about educating students to the highest degree.

Compound fractions, also known as mixed numbers, can be added and subtracted just like whole numbers. In this lesson, we will review what a compound fraction is and how to subtract compound fractions in number sentences.

Have you ever had a sleepover and ordered pizza with friends for dinner? Let's say 4 pizzas were ordered and after everyone finished eating there was still 1 whole pizza and half of another. How could we write that? We would put the numbers together as: 1 1/2. We say it as 1 and a half. This type of fraction is called a **compound fraction**, or a mixed number.

Let's start by looking at the steps we need to perform to subtract compound fractions:

Step 1: Change the compound fraction to an **improper fraction**, which is a fraction where the numerator is larger than the denominator.

Step 2: Find the common denominator, if necessary

Step 3: Subtract and convert back to a compound fraction

Step 4: Simplify, if necessary

Now, let's get back to our sleepover and talk about what type of drinks we have with pizza. For example, say there were 4 2/3 pints of juice and 2 1/3 pints were drunk with the pizza. How much juice is left? The number sentence would look like this:

Step 1: To change the compound fraction to an improper fraction, we simply multiply the whole number, in this case 4, by the denominator, in this case 3, and then add the numerator, in this case 2. This number is now our new numerator and the denominator remains the same.

We must do this to both fractions in the number sentence.

Now our new number sentence is:

Step 2: Denominators are the same

Step 3: Subtract the numerators while keeping the denominator the same. This gives us 7/3, an improper fraction. Change this back to a compound fraction by dividing the numerator by the denominator. Write down the whole number and the remainder becomes the new numerator and the denominator stays the same.

7 divided by 3 gives us 2 with 1 left over so the answer becomes 2 1/3.

Step 4: 2 1/3 is already simplified, so that is our answer.

Now let's look at an example where our denominators are not the same:

3 1/4 - 1 2/3

Step 1:

Step 2: Although there are several ways to find a common denominator, we are going to use the easiest way, a form of cross-multiplying that is merely finding the equivalent fractions of each fraction while at the same time giving them a common denominator. This is much easier than it sounds. Let's take a look:

As you can see, to easily find a common denominator, you multiply the numerator and denominator of *each* fraction by the denominator of the *other* fraction. So we now have 39/12 - 20/12

Step 3: When we subtract, we have 19/12. We need to change this improper fraction to a compound fraction by dividing the numerator by the denominator, writing the whole number down, and the remainder becomes the new numerator: 1 7/12

Step 4: 1 7/12 is as simplified as it gets, so we have our answer.

To subtract **compound fractions**, also known as mixed numbers, begin by changing the compound fractions to **improper fractions**. Then, find the common denominator of the two fractions and subtract. Remember to always change your answer back to a compound fraction and to simply if needed.

To unlock this lesson you must be a Study.com Member.

Create your account

Are you a student or a teacher?

Already a member? Log In

BackWhat teachers are saying about Study.com

Already registered? Log in here for access

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

You are viewing lesson
Lesson
18 in chapter 3 of the course:

Back To Course

Math for Kids23 chapters | 325 lessons

{{courseNav.course.topics.length}} chapters | {{courseNav.course.mDynamicIntFields.lessonCount}} lessons | {{course.flashcardSetCount}} flashcard set{{course.flashcardSetCoun > 1 ? 's' : ''}}

- Comparing Fractions: Lesson for Kids
- Equivalent Fractions: Lesson for Kids
- How to Add Fractions: Lesson for Kids
- Fractions Games for Kids
- Fractions to Decimals: Lesson for Kids
- Fractions: Lesson for Kids
- Numerator & Denominator Lesson for Kids
- Decimals: Lesson for Kids
- Multiplying Fractions by Whole Numbers: Lesson for Kids 3:04
- How to Simplify Fractions: Lesson for Kids
- Improper Fractions: Lesson for Kids
- What is a Benchmark Fraction on a Number Line? 3:48
- How to Add Mixed Fractions with Different Denominators
- Multiplying Compound Fractions
- Simplifying Compound Fractions
- Dividing Compound Fractions
- Adding Compound Fractions
- Subtracting Compound Fractions
- Multiplying Fractions with Like Denominators
- Subtracting Fractions with Like Denominators
- Reducing Fractions: Rules & Practice
- Definition of Simplest Form: Lesson for Kids
- How to Add Fractions with Unlike Denominators
- How to Subtract Fractions with Unlike Denominators
- Rules for Subtracting Fractions
- Rules for Multiplying Fractions
- Rules for Dividing Fractions
- Ordering Fractions on a Number Line
- Locating Fractions on a Number Line
- How to Add & Subtract Two Fractions with Like Denominators
- How to Find Equivalent Fractions on a Number Line
- How to Subtract Mixed Fractions with Unlike Denominators
- Go to Fractions for Elementary School

- Series 6 Exam: Study Guide & Practice
- Series 66 Exam: Study Guide & Practice
- Series 63 Exam: Study Guide & Practice
- Computer Science 330: Critical Infrastructure Security
- Real Estate Information Guide
- Understanding History & Primary Sources
- Romantic British Literature
- Modern Era British Literature
- Modern Era American Literature
- American Literary Developments
- CEOE Test Retake Policy
- Study.com Customer Service FAQs: Login, Cost & Support Email
- Study.com Refund: How to Request a Refund from Study.com
- California Real Estate Exam Dates
- How to Study for the FSA Exam
- FSA Test Cost
- How to Pass the FSA Reading Test

- Strain Energy: Definition & Calculation
- Medieval Africa: History & Culture
- How to Compute Derivatives
- Bromination of Acetanilide: Mechanism & Explanation
- Machiavelli's The Prince Discussion Questions
- Hard Times by Charles Dickens Discussion Questions
- Somewhere in the Darkness Discussion Questions
- Quiz & Worksheet - Pecuniary vs. Non-Pecuniary Damages
- Quiz & Worksheet - Cambodia Civil War Summary
- Quiz & Worksheet - Implicit Differentiation
- Quiz & Worksheet - Alkene Stability in Organic Chemistry
- Flashcards - Real Estate Marketing Basics
- Flashcards - Promotional Marketing in Real Estate
- Essay Topics for Teachers
- Algebra 2 Worksheets

- Supplemental Humanities: Study Aid
- History of Islam: Help & Review
- The Giver Study Guide
- MTTC Business, Management, Marketing & Technology (098): Practice & Study Guide
- Physics 101: Intro to Physics
- MTEL Middle School Math/Science: Magnetism & Electromagnetism
- NYSTCE Mathematics: Data Analysis & Statistics
- Quiz & Worksheet - Calculating the Project Specific Discount Rate
- Quiz & Worksheet - Capital Structure & Cost of Capital
- Quiz & Worksheet - Cash Budget
- Quiz & Worksheet - Allusions in The Scarlet Letter
- Quiz & Worksheet - Understanding Airport Taxiways

- Juror 3 in 12 Angry Men: Character Analysis
- How to Multiply by 9
- 504 Plans in Indiana
- Black History Bulletin Board Ideas
- Sequencing Activities for 2nd Grade
- Buoyancy Experiments for Kids
- Using Reading Level Correlation Charts
- 4th of July Activities for Kids
- Reading Comprehension Questions on the LSAT
- 3rd Grade Writing Prompts
- How Does LSAT Scoring Work?
- AP English Literature Question Types

- Tech and Engineering - Videos
- Tech and Engineering - Quizzes
- Tech and Engineering - Questions & Answers

Browse by subject