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This video is provided as supplementary material for courses taught at Howard
Community College, and in this video I'm going to talk about finding the percent
of the number. So here's the first example. I've got to find 40% of
13.
Now here's how the process works. I'm gonna take that 40% and turn
it into a decimal. I can do this by taking the decimal point, which I'm
assuming would be after the 40
and moving it two places to the left.
So if I had a decimal point after the 40 and I moved it two places left
I would have .40.
And then I'm going to take that and multiply it by the number that I'm find the percent of.
So I'll multiply .40
times 13.
So let's see what happens to this.
I'm going to drop that last zero, I don't really need it.
So I'm going to have .4 times 13.
4 times 3 is 2 and
carry a 1. 4 times 1 is 4plus 1 more equals 5,
and then I count the number of decimal places in
both of the numbers I'm multiplying. There's really only one decimal place so,
the answer is going to be 5.2.
Let's try another example.
This time we'll take a
percent of the decimal number.
So let's try 12%
of
3.52.
Once again
I'll turn 12% into a decimal.
I'm going to assume that there's an invisible decimal point after the 12.
I'll move it two places over to the left,
and that means my decimal version of 12%
will be
0.12.
And I multiply that
and
3.52.
So let's multiply that out.
I'll multiply
.12 times
3.52.
So two times 2 is 4.
Two times 5 is 10. I'll write the zero and carry the 1.
Two times 3 is 6, plus one more is 7.
I'll put a zero over here as a place holder and then I'll multiply by the 1.
Well, that's easy.
One times 2 is 2.
One times 5 is 5.
And one times 3 is 3.
Now I just have to add the numbers together.
So I've got four two two four and I have to count the decimal places that I'll need.
I've got two decimal places in each of the numbers I'm multiplying,
so I want to have 4 decimal places in my answer.
So my answer is going to be
0.4224.
And let's do one more. Let's take a percent of a fraction.
So I'm going to do
75%
of
1/5.
Now when you take a percent of the fraction, a lot of times it's easier to turn the percent
into a fraction, instead of turning it into a decimal.
So to turn a percent into a fraction, I take the number part of it,
the 75
and I just put that over
100.
And I'll reduce that. 75 over 100
would be equal to 3 over 4,
or 3/4.
And then I just multiply that 3/4 times the number that I was taking
the percent of, the 1/5.
So
3/4
times
1/5...
To multiply factions, I just multiply the numerators.
So I multiply 3 times 1 and get a 3.
And I multiply the denominators...
4 times 5 is 20.
So my end result is going to be 3 over 20.
So the basic process is going to be...
take your percent
and turn it into either a decimal...
very often it will be a decimal... and multiply it by the number you're taking
the percent of, or
if you're taking the percent of a fraction,
you might want to turn that percent into a fraction itself.
Reduce it as much as possible
and then multiply that fraction
times the
fraction you're taking a percent of.
And that's it.
Take care, I'll see you next time.