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Write 18% as a decimal and as
a fraction in simplest form.

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So let's do it as a decimal
first. So 18% is the same

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thing as 18 per 100,
or 18 per cent.

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I'm actually separating out the
percent, it's only going

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to be one word, but
I'm writing it as,

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literally, per cent.

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Cent means the same
thing as 100.

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So this literally means
18 per 100.

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Actually, I said I would do the
decimal first, but we can

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start putting it into a fraction
first. 18 per 100 as

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a fraction literally
means 18/100.

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We're literally doing the
fraction first. This literally

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means 18 per 100, or
18 hundredths.

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From here we can go straight
to a decimal or we could do

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this fraction in
simplest form.

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Let's do the decimal first, just
because that's actually

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what I said I would do first.
Let's do that first. This is

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the same thing as
18 hundredths.

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And we know how to write
that in decimal form.

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It's 0.18.

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You could view this as 1 tenth
and 8 hundredths, which is the

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same thing, or 10 hundredths and
8 hundredths, which is 18

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hundredths.

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So this is written
in decimal form.

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And if we write it as a
simplified fraction, we need

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to see if there is a common
factor for 18 and 100.

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And they're both even numbers,
so we know they're both

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divisible by 2, so let's divide
both the numerator and

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the denominator by 2.

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So we have 18 divided by 2
over 100 divided by 2.

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And we're going to get
18 divided by 2 is 9.

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100 divided by 2 is 50.

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And I don't think these guys
share any common factors.

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50 is not divisible by 3.

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9 is only divisible
by 3 and 1 and 9.

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So this is the fraction
in simplest form.

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So we have 18% is the same thing
as 0.18, which is the

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same thing, in simplest
form, as 9/50.

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Now, I went through a lot of
pain here to show you that

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this really just comes
from the word, from

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percent, from per 100.

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But if you ever were to see this
in a problem, the fast

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way to do this is to immediately
say, OK, if I have

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18%, you should immediately say,
anything in front of the

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percent-- that's that anything,
whatever this

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anything is-- it should be
equal to that anything.

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In this case it's 18/100.

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And another way to think
about it, you could

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view this as 18.0%.

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I just added a trailing zero
there, just so that you see

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the decimal, really.

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But if you want to express this
as a decimal without the

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percent, you just move
the decimal to

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the left two spaces.

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So if we move the decimal to the
left two spaces, one, two,

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this becomes 0.18.

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Or you could immediately
say that 18% as

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a fraction is 18/100.

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When you put it in simplified
form, it's 9/50.

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But you should also see that
18/100, and we have seen this,

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is the exact same thing as
18 hundredths, or 0.18.

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Hopefully, this made some
connections for you and didn't

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confuse you.

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