I show how to use the percent remaining method to solve percent change problems. It is a great method for finding the "new" amount in one step and can be used to solve a variety of percent change situations.

1. Percent Change using the
Percent Remaining Method
A great method for finding the new amount
in one step (and solving other problems).

2. If you have a percent increase
then the percent remaining is
greater than 100%.
To find the percent remaining
just add the percent increase
to 100%
•
•

3. If you have a percent decrease
then the percent remaining is
less than 100%.
To find the percent remaining
just subtract the percent
decrease from 100%
•
•

4. The four key numbers in percent change
situations are:
• Original (“old”) amount
• New amount
• Percent change
• Amount of change
 Note that I’m not including the percent remaining as
one the four key numbers, because it is a direct
result of percent change.


5. I like to use the template below for the four key
numbers in percent change situations
• Original (“old”) amount • New amount
• Percent change • Amount of change

6.  The Percent Remaining Method 
The key idea is

7. Example:

8. Summary (of the previous problem)
20%
$30 ?
?
20%
$30 $36
$6

9.  
This can be used, with one step of algebra, to find any
of the four numbers (you need to know two of them).

10. Set-up
17.4%
? $387.09
1998=previous year 1999=last year
?

11. Solution:

12. Closing Notes
• The percent remaining method works equally well on
percent decrease problems.
• Sometimes the percent remaining (written as a decimal,
113% = 1.13) is called the “multiplier.”
• The percent remaining method and the multiplier
concept is precisely what’s going on with exponential
functions (a topic for another day).
Remember:
 