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Subtracting Decimals

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    We need to calculate 9.005 minus
    3.6, or we could view it
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    as 9 and 5 thousandths
    minus 3 and 6 tenths.
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    Whenever you do a subtracting
    decimals problem, the most
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    important thing, and this is
    true when you're adding decimals as well,
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    is you have
    to line up the decimals.
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    So this is 9.005 minus 3.6.
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    So we've lined up the decimals,
    and now we're ready
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    to subtract.
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    Now we can subtract.
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    So we start up here.
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    We have 5 minus nothing.
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    You can imagine this 3.6, or
    this 3 and 6 tenths. We could
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    add two zeroes right here, and
    it would be the same thing as
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    3 and 600 thousandths, which is
    the same thing as 6 tenths.
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    And when you look at it that
    way, you'd say, OK, 5 minus 0
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    is nothing, and you just
    write a 5 right there.
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    Or you could have said, if
    there's nothing there, it
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    would have been 5 minus
    nothing is 5.
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    Then you have 0 minus
    0, which is just 0.
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    And then you have a 0 minus 6.
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    And you can't subtract
    6 from 0.
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    So we need to get something into
    this space right here,
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    and what we essentially are
    going to do is regroup.
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    We're going to take one 1 from
    the 9, so let's do that.
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    So let's take one 1 from the
    9, so it becomes an 8.
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    And we need to do something
    with that one 1.
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    We're going to put it
    in the tenths place.
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    Now remember, one whole
    is equal to 10 tenths.
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    This is the tenths place.
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    So then this will become 10.
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    Sometimes it's taught that
    you're borrowing the 1, but
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    you're really taking it, and
    you're actually taking 10 from
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    the place to your left.
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    So one whole is 10 tenths, we're
    in the tenths place.
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    So you have 10 minus 6.
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    Let me switch colors.
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    10 minus 6 is 4.
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    You have your decimal right
    there, and then you have 8
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    minus 3 is 5.
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    So 9.005 minus 3.6 is 5.405.
Title:
Subtracting Decimals
Description:

U03_L2_T1_we2 Subtracting Decimals

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Video Language:
English
Duration:
02:08

English subtitles

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