WEBVTT mathematics/basic-math/pyo
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Welcome back to Educator.com.
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This lesson, we are going to add and subtract fractions with common denominators.
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Right here, this is a fraction; the top number, 1, is called the numerator.
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This number right here is called the numerator.
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This bottom number, the 2, is called the denominator.
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When we add fractions, I have 2/6 plus 5/6; I am adding two fractions together.
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Let's look at their denominators.
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The denominator for this fraction is a 6; the denominator for this fraction is a 6.
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Once the denominators are the same, now they have a common denominator, then I can add the fractions.
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This 2/6 plus 5/6, I am going to add the numerators together.
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The numerator for this fraction is 2; the numerator for this fraction is a 5.
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2 plus 5; that is going to become my numerator for my answer
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For my denominator, it is going to stay the same as a 6.
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2/6 plus 5/6 is 7/6.
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Again the denominators for each fraction has to be the same.
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Then I take my numerators; I add them together; 2 plus 5 is 7.
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I do not add my denominators; my denominator has to stay the same as 6.
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2/6 over 5/6 is going to equal 7/6.
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Here we are subtracting these fractions, 7/8 minus 1/8.
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The denominator is the same; here is an 8 here.
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The denominator for this fraction is an 8.
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Therefore I can go ahead and subtract them.
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I am going to do 7 minus 1 which is 6.
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I take my denominator; that is going to stay the same.
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Do not subtract your denominators; it is 7 minus 1 which is 6.
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My denominator must stay the same as 8; 7/8 minus 1/8 is 6/8.
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My next example, 9/10 plus 3/10.
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I am going to take my numerators, add them together.
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It is 9 plus 3 which is 12 over... do not add your denominators.
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It is going to stay the same as a 10.
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9/10 plus 3/10 is going to equal 12/10.
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Again 11/20 plus 9/20, same denominator.
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I take 11, add it 9; I get 20 over... 20 plus 20?
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No, you do not add them together; the denominators are 20 here.
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The denominator for this one has to also be 20.
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Let's look at this fraction right here; my answer is 20/20.
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20/20, if the numerator and the denominator are the same, this is equal to 1.
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My answer would just be 1.
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The fourth example when we are adding and subtracting fractions, 23/95 plus 6/95.
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Whenever I add or subtract fractions, I have to make sure that the denominators for both fractions are the same.
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In this case, the denominator is 95; for this one, the denominator is 95.
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Since they are the same, I can go ahead and add the fractions together.
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I take the numerators which is 23 and 6; I am going to add them together.
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23 plus 6 is 29.
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For my denominator, denominator here is 95; here is 95.
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For my answer, the denominator also has to be a 95.
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You do not add the denominators together; the denominator stays the same as 95.
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23/95 plus 6/95 is going to equal 29/95.
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That is it for this lesson; thank you for watching Educator.com.