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Lecture Comments (1)

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Post by Ana Chu on February 4, 2014

Thank you, really good!

Adding and Subtracting Fractions with Same Denominators

Related Links

  • Numerator: The top number of a fraction
  • Denominator: The bottom number of a fraction
  • When we add fractions, we want the fractions to have the same denominator, or a common denominator
  • Add the numerators together and keep the denominator the same

Adding and Subtracting Fractions with Same Denominators

Add or subtract the fractions: [6/7] − [2/7]
[(4)/(7)]
Add or subtract the fractions: [6/9] − [1/9]
[(5)/(9)]
Add or subtract the fractions: [3/10] + [4/10]
[(7)/(10)]
Add or subtract the fractions: [2/4] + [1/4]
[(3)/(4)]
Add or subtract the fractions: [2/7] + [3/7]
[(5)/(7)]
Add or subtract the fractions: [12/30] + [18/30]
  • [12/30] + [18/30] = [30/30]
  • [30/30] = 1
1
Add or subtract the fractions: [12/15] − [8/15]
[(4)/(15)]
Add or subtract the fractions: [8/17] − [4/17]
[(4)/(17)]
Add or subtract the fractions: [11/45] + [13/45]
[(24)/(45)]
Add or subtract the fractions: [12/35] + [16/35]
[(28)/(35)]

*These practice questions are only helpful when you work on them offline on a piece of paper and then use the solution steps function to check your answer.

Answer

Adding and Subtracting Fractions with Same Denominators

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • Same Denominator 0:11
    • Numerator and Denominator
    • Example: 2/6 + 5/6
  • Extra Example 1: Add or Subtract the Fractions 2:02
  • Extra Example 2: Add or Subtract the Fractions 2:45
  • Extra Example 3: Add or Subtract the Fractions 3:17
  • Extra Example 4: Add or Subtract the Fractions 4:05

Transcription: Adding and Subtracting Fractions with Same Denominators

Welcome back to Educator.com.0000

This lesson, we are going to add and subtract fractions with common denominators.0002

Right here, this is a fraction; the top number, 1, is called the numerator.0013

This number right here is called the numerator.0022

This bottom number, the 2, is called the denominator.0029

When we add fractions, I have 2/6 plus 5/6; I am adding two fractions together.0042

Let's look at their denominators.0050

The denominator for this fraction is a 6; the denominator for this fraction is a 6.0052

Once the denominators are the same, now they have a common denominator, then I can add the fractions.0059

This 2/6 plus 5/6, I am going to add the numerators together.0068

The numerator for this fraction is 2; the numerator for this fraction is a 5.0075

2 plus 5; that is going to become my numerator for my answer0080

For my denominator, it is going to stay the same as a 6.0088

2/6 plus 5/6 is 7/6.0096

Again the denominators for each fraction has to be the same.0100

Then I take my numerators; I add them together; 2 plus 5 is 7.0105

I do not add my denominators; my denominator has to stay the same as 6.0111

2/6 over 5/6 is going to equal 7/6.0116

Here we are subtracting these fractions, 7/8 minus 1/8.0124

The denominator is the same; here is an 8 here.0130

The denominator for this fraction is an 8.0133

Therefore I can go ahead and subtract them.0136

I am going to do 7 minus 1 which is 6.0139

I take my denominator; that is going to stay the same.0147

Do not subtract your denominators; it is 7 minus 1 which is 6.0150

My denominator must stay the same as 8; 7/8 minus 1/8 is 6/8.0156

My next example, 9/10 plus 3/10.0166

I am going to take my numerators, add them together.0174

It is 9 plus 3 which is 12 over... do not add your denominators.0177

It is going to stay the same as a 10.0186

9/10 plus 3/10 is going to equal 12/10.0189

Again 11/20 plus 9/20, same denominator.0199

I take 11, add it 9; I get 20 over... 20 plus 20?0206

No, you do not add them together; the denominators are 20 here.0216

The denominator for this one has to also be 20.0221

Let's look at this fraction right here; my answer is 20/20.0225

20/20, if the numerator and the denominator are the same, this is equal to 1.0231

My answer would just be 1.0240

The fourth example when we are adding and subtracting fractions, 23/95 plus 6/95.0247

Whenever I add or subtract fractions, I have to make sure that the denominators for both fractions are the same.0258

In this case, the denominator is 95; for this one, the denominator is 95.0265

Since they are the same, I can go ahead and add the fractions together.0270

I take the numerators which is 23 and 6; I am going to add them together.0276

23 plus 6 is 29.0282

For my denominator, denominator here is 95; here is 95.0287

For my answer, the denominator also has to be a 95.0293

You do not add the denominators together; the denominator stays the same as 95.0298

23/95 plus 6/95 is going to equal 29/95.0304

That is it for this lesson; thank you for watching Educator.com.0313