Understanding Percentages

Understanding Percentages

Author: Michael Morgan

The objective of this packet is to develop an understand of new terms and definitions. Also, you will learn what a percentage is and how to use proportions to solve percentage problems.

Learn how percentages work and are calculated

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What is a Percentage?

By this point in time, you have probably learned about ratios and proportions. Now you're on to percentages, but what exactly is a percentage?

A percentage is a way of expressing a number as a fraction of 100 (per cent meaning "per hundred"). It is often denoted using the percent sign, "%", or the abbreviation "pct". For example, 45% (read as "forty-five percent") is equal to 45 / 100, or 0.45.

Understanding Percentages

Remember, percentage is nothing more than a fancy word for proportion.

NOTE: Error in Video

3400/40 is 85. 


To get the final discounted price, you have to take 100-85. This will give you the final discount rate of 15%

Practice Problems

Clicking the link below will lead you to a website with many variations of practice problems.

The type of examples includes:

  • Fractions to percents
  • Decimals to percents
  • Calculating percentage values
  • Calculating using percentage values. 






1. Assume you are the manager of a convenience store, and the local sales tax is 6.5%.  At the end of the day, you find sales totaling $3210.  What is the amount of tax that will be added on to the sales?


2. A gumball machine contains 51 blue, 128 green, and 93 red gumballs.  Find the percent of the gumballs that are blue.


3. The regular price of a tool kit is $39.99.  If the tool kit is marked 15% off, what is the sale price?


4. Mrs. Kim is a real estate broker.  Her salary is $2650 per month, plus 0.25% of sales.  To earn $5000 in a month, how much does she need to sell?


5. Mandy bought a sweater that was marked down 20%.  What was the original cost of the sweater if she saved $9.00?




1. $3210  *  .065  =  $208.65

2. Total gumballs  =  51  +  128  +  93  =  272

     51/272  =  .1875   =   18.75%

3.  15%  *  $39.99  =  $6.00

 Sale price is  $39.99  -  $6.00  =  $33.99

4. $5000  -  $2650  =  $2350    This is her sales commission

    .25%  *  amount of sales  =  $2350

     .0025   *   x   =   2350

     x    =   $940,000

5.  20%  of the cost  =  $9.00

      cost   =   $45