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Adding fractions (ex 1)

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    Let's add four elevenths to nine over thirteen
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    In order to add these two fractions we need to find a common denominator
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    And that common denominator used to be the least common multiple of eleven and thirteen
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    And these two numbers don't share any common factors
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    So their least common multiple is really just going to be the product of eleven and thirteen
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    So we could say thirteen times eleven
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    Thirteen times one is thirteen
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    Thirteen times another one is thirteen
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    Or you could say thirteen times ten is a hundred and thirty
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    And we get: three, four, one - one hundred and forty-three
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    So that's going to be our common denominator
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    So I'll write it over here:
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    Something over one hundred and forty-three plus
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    Something else over one hundred and forty-three
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    And to go from four elevenths to something over one forty-three
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    We multiply the eleven times thirteen
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    --Or we multiply the denominator times thirteen--
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    So we're going to have to multiply the numerator times thirteen as well
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    And four times thirteen--let's see: four times ten is forty
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    Four times three is twelve, so it gives us fifty-two
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    And you can work that out by hand if you like
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    Four times thirteen is fifty-two
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    And then to go from thirteen to one forty-three we multiply by eleven
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    So if we multiply the denominator by eleven
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    (if we don't want to change the value of the fraction)
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    We have to multiply the numerator by eleven
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    Nine times eleven is ninety-nine
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    And now we're ready to add: this is equal to--our common denominator is one hundred and forty-three
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    And fifty-two plus ninety-nine
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    --Fifty-two plus a hundred would be one hundred and fifty two
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    And this is going to be one less than that
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    So it's going to be one hundred and fifty-one
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    And I think that's about as simplified as we can get
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    As far as I know, it doesn't look like there are any common factors between one fifty-one and one forty-three
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    So we just get one fifty-one over one forty-three
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    --We can write this as a mixed number
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    Because one forty-three goes into one fifty-one one time
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    One times one forty-three is one forty-three
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    When you subtract--let's see, this can become an eleven
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    This is a four
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    Eleven minus three is eight
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    You have a remainder of eight
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    So one fifty-one over one forty-three is the same thing as one and eight one forty-thirds
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    And now it becomes even more clear that these can't be simplified anymore
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    And we are done--this is the same thing as one and eight one forty-thirds
Title:
Adding fractions (ex 1)
Description:

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Video Language:
English
Duration:
02:33
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