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What is the cost of 14.6 gallons
of gasoline at $2.70

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per gallon?

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So we have 14.6 gallons,
and each gallon's

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going to cost $2.70.

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Or we can even view $2.70
as 2.7 dollars.

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Let's just multiply times 2.7.

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It makes things a little
bit simpler.

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I think you'll appreciate $2.70
is the same thing as 2.7

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dollars per gallon.

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So let's multiply this out.

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So first we have, and just as a
reminder, when you multiply

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decimals, you just have to treat
the numbers like whole

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numbers and then worry about
the decimals later.

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So right now, we can just view
this as 146 times 27, and then

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we'll worry about
the decimals.

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So first we have
a 7 times a 6.

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7 times 6 is 42.

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Regroup the 4.

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7 times 4 is 28, plus 4 is 32.

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Regroup the 3.

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7 times 1 is 7, plus 3 is 10.

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So we get 7 times
146 is 1,022.

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Now we're going to
deal with this 2.

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But this 2, at least before we
consider the decimal, is

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really a 20.

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So we're going to
put a 0 here.

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We're doing it exactly the same
way we do a traditional

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multiplication problem.

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We're ignoring the
decimals for now.

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2 times 6 is 12.

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Carry the 1, or regroup the 1.

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We can ignore these
guys right now.

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2 times 4 is 8, plus 1 is 9.

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2 times 1 is 2, and
now we can add.

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And we get 2 plus 0 is 2.

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2 plus 2 is 4.

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0 plus 9 is 9.

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1 plus 2 is 3.

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Now we've figured out what
146 times 27 is.

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It's 3,942.

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But this wasn't 146 times 27.

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It was 14.6 times 2.7.

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So now we have to worry
about the decimals.

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We just count how many numbers
are sitting behind decimals.

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We have one right there and
a second one right there.

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So our product has to have
two numbers to the

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right of the decimal.

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So one, two, stick it
right over there.

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So for 14.6 gallons of gas at
$2.70 per gallon, it's going

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to cost $39.42.

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