## Dividing Decimals

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We need to divide 0.25
into 1.03075.
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Now the first thing you want to
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number that you're dividing into
the other number, is a
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decimal, is to multiply it by
10 enough times so that it
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becomes a whole number
so you can shift the
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decimal to the right.
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So every time you multiply
something by 10, you're
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shifting the decimal over
to the right once.
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So in this case, we want
to switch it over the
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right once and twice.
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So 0.25 times 10 twice is the
same thing as 0.25 times 100,
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and we'll turn the
0.25 into 25.
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Now if you do that with the
divisor, you also have to do
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that with the dividend,
the number that
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you're dividing into.
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So we also have to multiply this
by 10 twice, or another
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way of doing it is shift
the decimal over
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to the right twice.
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So we shift it over
once, twice.
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It will sit right over here.
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And to see why that makes
sense, you just have to
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realize that this expression
right here, this division
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problem, is the exact same
thing as having 1.03075
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divided by 0.25.
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And so we're multiplying
the 0.25 by 10 twice.
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We're essentially multiplying
it by 100.
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Let me do that in a
different color.
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We're multiplying it by 100
in the denominator.
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This is the divisor.
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We're multiplying it by 100, so
we also have to do the same
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thing to the numerator, if we
don't want to change this
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expression, if we don't want
to change the number.
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So we also have to multiply
that by 100.
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And when you do that,
this becomes 25, and
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this becomes 103.075.
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Now let me just rewrite this.
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Sometimes if you're doing this
in a workbook or something,
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you don't have to rewrite it as
long as you remember where
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the decimal is.
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But I'm going to rewrite
it, just so it's
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a little bit neater.
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So we multiplied both
the divisor and
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the dividend by 100.
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This problem becomes 25
divided into 103.075.
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These are going to result in
the exact same quotient.
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They're the exact same fraction,
if you want to view
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it that way.
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We've just multiplied both the
numerator and the denominator
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by 100 to shift the decimal
over to the right twice.
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Now that we've done that,
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So the first thing, we have 25
here, and there's always a
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little bit of an art to dividing
something by a
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multiple-digit number, so we'll
see how well we can do.
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So 25 does not go into 1.
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25 does not go into 10.
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25 does go into 103.
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We know that 4 times 25
is 100, so 25 goes
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into 100 four times.
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4 times 5 is 20.
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4 times 2 is 8, plus 2 is 100.
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We knew that.
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Four quarters is \$1.00.
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It's 100 cents.
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And now we subtract.
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103 minus 100 is going to
be 3, and now we can
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bring down this 0.
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So we bring down that 0 there.
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25 goes into 30 one time.
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And if we want, we could
immediately put
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this decimal here.
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We don't have to wait until
the end of the problem.
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This decimal sits right in that
place, so we could always
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have that decimal sitting right
there in our quotient or
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So we were at 25 goes
into 30 one time.
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1 times 25 is 25, and then
we can subtract.
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30 minus 25, well,
that's just 5.
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I mean, we can do all this
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regrouping.
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This can become a 10.
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This becomes a 2.
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10 minus 5 is 5.
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2 minus 2 is nothing.
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But anyway, 30 minus 25 is 5.
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Now we can bring down this 7.
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25 goes into 57 two
times, right?
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25 times 2 is 50.
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25 goes into 57 two times.
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2 times 25 is 50.
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And now we subtract again.
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57 minus 50 is 7.
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And now we're almost done.
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We bring down that 5
right over there.
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25 goes into 75 three times.
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3 times 25 is 75.
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3 times 5 is 15.
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Regroup the 1.
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We can ignore that.
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That was from before.
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3 times 2 is 6, plus 1 is 7.
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So you can see that.
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And then we subtract, and then
we have no remainder.
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So 25 goes into 103.075 exactly
4.123 times, which
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makes sense, because 25 goes
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This is a little bit larger than
100, so it's going to be
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a little bit more
than four times.
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And that's going to be the
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number of times that 0.25
goes into 1.03075.
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This will also be 4.123.
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So this fraction, or this
expression, is the exact same
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thing as 4.123.
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And we're done!
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Title:
Dividing Decimals
Description:

U03_L2_T2_we3 Dividing Decimals

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Video Language:
English
Duration:
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