## Mulitplyling Decimals 3

• 0:00 - 0:00
• 0:00 - 0:07
What is the cost of 14.6 gallons
of gasoline at \$2.70
• 0:07 - 0:08
per gallon?
• 0:08 - 0:16
So we have 14.6 gallons,
and each gallon's
• 0:16 - 0:17
going to cost \$2.70.
• 0:17 - 0:22
Or we can even view \$2.70
as 2.7 dollars.
• 0:22 - 0:25
Let's just multiply times 2.7.
• 0:25 - 0:27
It makes things a little
bit simpler.
• 0:27 - 0:30
I think you'll appreciate \$2.70
is the same thing as 2.7
• 0:30 - 0:32
dollars per gallon.
• 0:32 - 0:35
So let's multiply this out.
• 0:35 - 0:39
So first we have, and just as a
reminder, when you multiply
• 0:39 - 0:42
decimals, you just have to treat
the numbers like whole
• 0:42 - 0:45
the decimals later.
• 0:45 - 0:49
So right now, we can just view
this as 146 times 27, and then
• 0:49 - 0:51
the decimals.
• 0:51 - 0:54
So first we have
a 7 times a 6.
• 0:54 - 0:57
7 times 6 is 42.
• 0:57 - 0:59
Regroup the 4.
• 0:59 - 1:03
7 times 4 is 28, plus 4 is 32.
• 1:03 - 1:05
Regroup the 3.
• 1:05 - 1:09
7 times 1 is 7, plus 3 is 10.
• 1:09 - 1:14
So we get 7 times
146 is 1,022.
• 1:14 - 1:16
Now we're going to
deal with this 2.
• 1:16 - 1:18
But this 2, at least before we
consider the decimal, is
• 1:18 - 1:19
really a 20.
• 1:19 - 1:22
So we're going to
put a 0 here.
• 1:22 - 1:25
We're doing it exactly the same
• 1:25 - 1:26
multiplication problem.
• 1:26 - 1:28
We're ignoring the
decimals for now.
• 1:28 - 1:29
2 times 6 is 12.
• 1:29 - 1:32
Carry the 1, or regroup the 1.
• 1:32 - 1:34
We can ignore these
guys right now.
• 1:34 - 1:38
2 times 4 is 8, plus 1 is 9.
• 1:38 - 1:41
2 times 1 is 2, and
• 1:41 - 1:45
• 1:45 - 1:47
And we get 2 plus 0 is 2.
• 1:47 - 1:49
2 plus 2 is 4.
• 1:49 - 1:52
0 plus 9 is 9.
• 1:52 - 1:55
1 plus 2 is 3.
• 1:55 - 1:59
Now we've figured out what
146 times 27 is.
• 1:59 - 2:01
It's 3,942.
• 2:01 - 2:03
But this wasn't 146 times 27.
• 2:03 - 2:06
It was 14.6 times 2.7.
• 2:06 - 2:08
So now we have to worry
• 2:08 - 2:11
We just count how many numbers
are sitting behind decimals.
• 2:11 - 2:14
We have one right there and
a second one right there.
• 2:14 - 2:17
So our product has to have
two numbers to the
• 2:17 - 2:18
right of the decimal.
• 2:18 - 2:21
So one, two, stick it
right over there.
• 2:21 - 2:26
So for 14.6 gallons of gas at
\$2.70 per gallon, it's going
• 2:26 - 2:28
to cost \$39.42.
• 2:28 - 2:31
Title:
Mulitplyling Decimals 3
Description:

U03_L2_T2_we5 Mulitplyling Decimals 3

more » « less
Video Language:
English
Duration:
02:32
 brettle edited английски език subtitles for Mulitplyling Decimals 3 brettle edited английски език subtitles for Mulitplyling Decimals 3 brettle edited английски език subtitles for Mulitplyling Decimals 3

Incomplete

• brettle