Percent of a Number Test 1
7th Grade Lesson
for Tuesday
November 22nd
In this lesson, you will continue to work
on proportions and percents.

In particular, you'll be calculating the
percent of a number


First, it's important to understand how calculating
a percent of a number is just like calculating a
proportion. 

For example, 40% of 200

We know that 40% is the same as
40 out of 100.

We can write that as a fraction:

40% =
100
40
Since...
We can then compare that to an equivalent
proportion.  This is like saying...

If 40 out of 100 students like ham sandwiches,
how many in a school of 1000 will like them?
To solve this, we'd write a proportion:

x =
100
40
40 x 1000
100
40% =
=
1000
100
= 400
x
40
Instead of saying 40 out of 100, we could just say
40%. 

If 40% of the students like ham sandwiches, how
many students out of 1000 will like them?

This would be the same proportion:
x =
100
40
40 x 1000
100
=
1000
= 400
x
Let's make sure you are getting this:

If 60% of the students like Turkey sandwiches,
how many out of 800 will like them?

Fill in the missing spaces and use your calculator
to find the final answer.
=
x=
This is the last slide for Part I.  If you did this
correctly, you will receive a 100% on this portion.

If there is a mistake, it will require you to retake
this portion.  Please take your time and read each
slide carefully, so that you'll be ready to go on
to the next section.
Intereseko beste azterketa batzuk :

Azterketa honekin sortua That Quiz — matematika eta gai askotako ariketak egiten diren tokia.