# Introduction to Percentages

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If there is a 50% off sale on at the store, most people will realize that everything is half its original price.

50% (or 50 percent) is equal to one half or ½ or 0.5

If 4 out of 5 people who visit the store buy at least one item, then the proportion of buyers is 4/5, or four fifths, or 80%.

How did we work out that 4/5 is 80% ?

To make any fraction a percentage we need to do top divided by bottom, and then multiply by 100. (4 divided by 5 x 100 on a calculator should give 80%).

Don’t worry too much about all that right now, because we will do a whole separate lesson on changing fractions to percents.

Percent simply means out of 100 or /100.

80% means 80 out of every 100 which can also be written as 80/100.

In countries like the USA and Australia, if we have 80 cents, then we have 80% of a dollar.

We would only need another 20 cents (or 20%) to get ourselves a full dollar.

Watch the following video which introduces percents in less than three minutes.

Common Percent Values

The following common Percentage Values need to be memorised.

It is very useful to have an idea of what fraction of a whole amount any given percentage is.

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Online Lesson on Percentages

Do the following lesson from “Math Goodies” and then try the online test at the bottom of the page.

This does advance into areas we have not looked at yet, and so if it is too hard, then skip it until you have learned a bit more about Percentages.

Click the following link to do the free online lesson.

http://www.mathgoodies.com/lessons/vol4/meaning_percent.html

This short video is a little bit out there. It involves Percentages and their Decimal equivlanets, and covers the basic out of 100 concept.

Visualizing Percents Online Game

We recommend playing the following game which greatly helps to visualise Percentage Amounts.

This is not so much of a game as an activity, where percentages can be viewed as part of a Pizza, a number of people, how full a jug is, or how much chocolate is left.

To start the game, click on one of the bottom icons such as Pizza, People, Jug, or Chocolate Bar.

We then simply click down and hold the mouse button, and then drag the % value from the right hand table, into the black action box, and the picture then changes to show us the percent amount we have chosen.

Click the following link to play this game.

http://www.bbc.co.uk/skillswise/game/ma16perc-game-percentages-of-something

Using Percentages for Comparing

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In a recent survey 25 out of 28 students in a class said that they had used Facebook. Eight girls sitting together at a fast food restaurant were also surveyed and 7 out of 8 had used Facebook.

To answer this question we would need to know if 25/28 is a bigger fraction than 7/8.

This is not at all easy to figure out.

To get an answer for situations like this we use Percentages.

25/28 as a Percentage is 25/8 x 100 = 89%.

7/8 as a Percentage is 7/8 x 100 = 88%.

89% is larger than 88% (just like 89 is bigger than 88), and so the class of students had a very slightly higher proportion of people who had used Facebook.

Percentages are often used for comparing items such as survey results.

Online Quiz One on Percentages

This multiple choice quiz can be done Online, or you can click the Download button and Download it as a PDF or a DOC.

There are three levels of Quizes that can be done, and each of the three quizes has 10 questions.

If the Quiz is done online then a final score and fully worked answers are given after the quiz is completed.

Click the following link to do the Quiz.

http://www.bbc.co.uk/skillswise/quiz/ma16perc-e3-quiz

Online Quiz Two on Percentages

This multiple choice quiz can be done Online, or you can click the Download button and Download it as a PDF or a DOC.

Many of the questions on this quiz we will cover in later lessons, so do not be worried if you do not score well on it.

There are three levels of Quizes that can be done, and each of the three quizes has 10 questions.

If the Quiz is done online then a final score and fully worked answers are given after the quiz is completed.

Click the following link to do the Quiz.

http://www.bbc.co.uk/skillswise/quiz/ma16perc-l1-quiz

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