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Math for Kids23 chapters | 325 lessons

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Instructor:
*Emily Hume*

Emily is a Reading Specialist and Literacy coach in a public elementary school with a Master's Degree in Elementary Education.

Even though you may not realize it, fractions are all around you, so knowing how to work with them is an important skill. In this lesson, you will learn how to subtract fractions with like denominators as well as those with different denominators.

You are sharing an apple with a friend. The apple is cut into three equal slices, or fractions, of the whole apple. Your friend quickly gobbles down a slice! Do you get your fair share of the apple, or did your friend eat too much? What fraction of the apple is left? You must subtract to find out.

However, like with so many things in life and in math, there are rules that must be followed in order to successfully engage in some fraction subtraction action. So, let's take a look!

Rule 1: The fractions must have a common denominator.

What this means is that the **denominators**, or the bottom numbers, of the fractions, must be the same, what we call **common denominators**. If they are not the same, then we will find the common denominator and make them the same.

Rule 2: Once you have a common denominator, it does not change.

In other words, when you are subtracting your fractions, you are only subtracting the numerators, or the numbers on top.

Rule 3: Simplify the answer, if necessary.

If your answer has a numerator and a denominator that share a common factor, use that factor to reduce the fraction.

Here's an example of a fraction subtraction problem that already has common denominators:

Since the denominators are the same, the only thing you have to do is subtract the top numbers! The denominator stays the same. So for this problem, 2 - 1 = 1, then the 3 stays the same so

2/3 - 1/3 = 1/3

Let's look at this fraction subtraction problem with different denominators:

7/8 - 1/4 = ?

By using **equivalent fractions**, fractions that look different but actually represent the same number, we can find the common denominator and can turn 1/4 into 2/8, which now has the same denominator as 7/8.

So, 1/4 = 2/8. Here's a picture!

Now that you have found the equivalent fraction to 1/4 (2/8), you are ready to subtract!

7/8 - 2/8 = 5/8 because 7 - 2 = 5 and the denominator (8) stays the same.

In this example, let's combine everything we've learned:

1/2 - 1/6 = ?

Rule 1 says our denominators must be the same. Since they are not, let's find the common denominator:

Using what we just learned about equivalent fractions, we multiply 1/2 x 3/3 and get 3/6 which now has the same denominator, 6, as our other fraction.

Rule 2 says that once we have a common denominator, we just subtract the numerators and keep the same denominator

3/6 - 1/6 = 2/6

Rule 3 says to simplify, or reduce, the fraction. In 2/6, both the 2 and the 6 can be evenly divided by 2.

2/6 ÷ 2/2 = 1/3.

See, it's as easy as Rule 1, 2 and 3!!

There are three rules to follow when subtracting fractions. The first rule is that our fractions must have **common denominators**. If the denominators in each fraction are not the same, use the **equivalent fraction** process to make them the same before moving onto the second rule, which is that you subtract the numerators only, keeping the denominator the same. Finally, the third rule states that, if necessary, simplify your answer!

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Math for Kids23 chapters | 325 lessons

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- 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
- How to Subtract Fractions with Variables
- 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 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

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