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Numerator and Denominator of a Fraction

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    We're asked to identify the
    numerator and denominator in
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    the fraction 3 over 4, or 3/4.
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    So let's rewrite this just
    so it's nice and big.
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    So let me just write
    the fraction.
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    So we have 3 over 4, 3/4.
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    Now, they want us to identify
    the numerator and the
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    denominator.
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    So the numerator is just the
    number on top, so the
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    numerator is the
    3 right there.
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    And then they want us to
    find the denominator.
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    The denominator is just the
    number on the bottom.
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    It's the 4.
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    So if they say what's
    the numerator?
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    3.
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    What's the denominator?
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    It's 4, just the number
    on the bottom.
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    They could've just called this
    the number on the bottom.
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    They could've just called
    this the number on top.
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    Now to think about what this
    represents, what this fraction
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    represents, you can think
    of it as three out of
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    four pieces of a pie.
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    That's how I think about it.
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    So you can imagine, the
    denominator tells us, what are
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    we taking a fraction out of or
    how many pieces are there?
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    So let's imagine a
    pie like this.
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    So we could draw like
    a square pie.
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    So this is what the denominator
    represents.
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    This is what the number on
    the bottom represents.
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    And then 3 says, we are
    representing three of those
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    four pieces.
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    So this 3 tells us that out of
    4 possible ones, I guess you
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    could think of it, we are using
    three, or maybe we're
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    eating three.
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    So you can imagine if someone
    says I ate three-fourths of a
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    pie-- this would be read as
    three-fourths-- they're eating
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    the blue portion of the pie
    if we cut it this way.
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    If we imagine a round pie,
    it would look like this.
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    Let me draw a round pie.
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    So that is my round pie.
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    Let me cut it into four
    equal pieces or
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    roughly equal pieces.
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    And if someone says I ate
    three-fourths of this pie,
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    where the 3 is the numerator,
    and then the 4, and you'd read
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    that as three-fourths, the 4 is
    the denominator, they would
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    eat this much of the pie.
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    They would eat 3 of
    the 4 pieces.
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    So this is is one piece, this
    is two pieces, and this is
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    three pieces.
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    So you could imagine the 4, the
    denominator represents the
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    total number of pieces in the
    pie, and then the 3 represents
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    how many of those we ate.
Title:
Numerator and Denominator of a Fraction
Description:

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Video Language:
English
Team:
Khan Academy
Duration:
02:31

English subtitles

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