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# The meaning of percent

Let's think about what percent really means by looking at a 10 by 10 grid. Created by Sal Khan and Monterey Institute for Technology and Education.

Video transcript

We're asked to shade 20%
of the square below. Before doing that, let's
just even think about what percent means. Let me just rewrite it. 20% is equal to-- I'm just
writing it out as a word-- 20 percent, which literally
means 20 per cent. And if you're familiar with the
word century, you might already know that cent
comes from the Latin for the word hundred. This literally means you
can take cent, and that literally means 100. So this is the same thing
as 20 per 100. If you want to shade 20%, that
means, if you break up the square into 100 pieces, we
want to shade 20 of them. 20 per 100. So how many squares have
they drawn here? So if we go horizontally right
here, we have one, two, three, four, five, six, seven, eight,
nine, ten squares. If we go vertically, we have
one, two, three, four, five, six, seven, eight, nine, ten. So this is a 10 by 10 square. So it has 100 squares here. Another way to say it is that
this larger square-- I guess that's the square that they're
talking about. This larger square is a broken
up into 100 smaller squares, so it's already broken
up into the 100. So if we want to shade 20% of
that, we need to shade 20 of every 100 squares that
it is broken into. So with this, we'll just
literally shade in 20 squares. So let me just do one. So if I just do one square, just
like that, I have just shaded 1 per 100
of the squares. 100 out of 100 would
be the whole. I've shaded one of them. That one square by itself
would be 1% of the entire square. If I were to shade another one,
if I were to shade that and that, then those two
combined, that's 2% of the entire square. It's literally 2 per 100,
where 100 would be the entire square. If we wanted to do 20, we do
one, two, three, four-- if we shade this entire row, that
will be 10%, right? One, two, three, four, five,
six, seven, eight, nine, ten. And we want to do 20, so that'll
be one more row. So I can shade in this whole
other row right here. And then I would have shaded
in 20 of the 100 squares. Or another way of thinking about
it, if you take this larger square, divide it into
100 equal pieces, I've shaded in 20 per 100, or 20%, of the
entire larger square. Hopefully, that makes sense.