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## 7th grade foundations (Eureka Math/EngageNY)

### Unit 4: Lesson 1

Topic A: Foundations# Identifying percent amount and base

Sal identifies the percent, amount, and base in a percent problem. Created by Sal Khan and Monterey Institute for Technology and Education.

## Video transcript

We're asked to identify
the percent, amount, and base in this problem. And they ask us 150
is 25% of what number? So another way to think about
it is 25% times some number. So I'll do 25% in yellow. And 25% times some
number is equal to 150. So the percent is
pretty easy to spot. We have a 25% right over here. So this is going
to be the percent. And we're multiplying the
percent times some base number. So this right over
here is the base. So we have the percent
times the base. We have the percent times the
base is equal to some amount. And you could try to
solve this in your head. This is essentially
saying 25% of some number, 25% times some number
is equal to 150. If it helps, we
could rewrite this as 0.25, which is the
same thing as 25%. 0.25 times some number
is equal to 150. And one interesting thing
is just to think about, should that number be
larger or smaller than 150? Well, if we only take
25% of that number, if we only take 25
hundredths of that number, if we only take
1/4 of that number, because that's what
25 hundredths is, or that's what 25%
is, we get 150. So this number needs
to be larger than 150. In fact, it has to be
larger than 150 by 4. And to actually figure
out what the number is, we can actually multiply. Since this, what's
on the left-hand side is equal to the right-hand
side, if we want to solve this, we can multiply both sides by 4. If we say, look, we have
some value over here, we're going to multiply it by 4. In order for it
to still be equal, we have to multiply 150 times 4. 4 times 0.25, or 4 times
25%, or 4 times 1/4, this is just going to be 1. And we're going to get our
number is equal to 150 times 4 or it is equal to 600. And that makes sense,
25% of 600 is 150. 1/4 of 600 is 150.