percents 07/27/12lntaylor ©. table of contents learning objectives straight percent change in...

Percents

07/27/12 lntaylor ©

Table of Contents

Learning Objectives

Straight Percent

Change in Percent

Percent/Fraction/Decimal Equivalents Table

Practice

07/27/12 lntaylor ©

LO1:

LO2:

Define and differentiate fraction, percent and decimal equivalents

Memorize the Equivalents chart

07/27/12 lntaylor ©TOC

Learning Objectives

Def1:

Def2:

Fraction is a rational number that represent part of a whole(2/7 means 2 out of 7 total)

Decimal equivalent represents a number between -1 < 0 < 1(- 0.25 is the same as – ¼; 0.50 is the same as ½)

07/27/12 lntaylor ©TOC

Definitions

Def3: Percent is a number followed by a % that represents theIncrease or decrease between two numbers100% increase would mean the beginning number doubled50% decrease means the beginning number reduced by half

PK1: Knowledge of fractions and decimals

07/27/12 lntaylor ©TOC

Previous Knowledge

07/27/12 lntaylor ©TOC

Straight Percent

Step1:

Step2:

You absolutely must carefully read & understand percent questionsbefore you start the problem!!!!!!

You have two choices of where to start this problem (3 or 6)Only one will give you the correct answer!

07/27/12 lntaylor ©TOC

3 is what percent of 6?

Step3: Hint: Look for the number following the word “of”That number is the denominatorThe other number is the numerator

Step4: Convert the fraction to a decimal equivalentEquivalent means the fraction and decimal are exactly the same numberEven if they do not look the same

Step5: Covert decimal to percent by moving the decimal 2 places to the right

_63

3 1 6 2

0.50 = 50%

of 63

= = 0.50

Now you try

5 is what percent of 40?

07/26/12 lntaylor ©TOC

Step1:

Step2:

You absolutely must carefully read & understand percent questionsbefore you start the problem!!!!!!

You have two choices of where to start this problem (5 or 40)Only one will give you the correct answer!

07/27/12 lntaylor ©TOC

5 is what percent of 40?

Step3: Hint: Look for the number following the word “of”That number is the denominatorThe other number is the numerator

Step4: Convert the fraction to a decimal equivalentEquivalent means the fraction and decimal are exactly the same numberEven if they do not look the same

Step5: Covert decimal to percent by moving the decimal 2 places to the right

__40

5

5 1 40 8

0.125 = 12.5%

of 405

= = 0.125

Now you try

40 is what percent of 5?

07/26/12 lntaylor ©TOC

Step1:

Step2:

You absolutely must carefully read & understand percent questionsbefore you start the problem!!!!!!

You have two choices of where to start this problem (40 or 5)Only one will give you the correct answer!

07/27/12 lntaylor ©TOC

40 is what percent of 5?

Step3: Hint: Look for the number following the word “of”That number is the denominatorThe other number is the numerator

Step4: Convert the fraction to a decimal equivalentEquivalent means the fraction and decimal are exactly the same numberEven if they do not look the same

Step5: Covert decimal to percent by moving the decimal 2 places to the right

__ 5

40

40 8 5 1

8.0 = 800%

of 540

= = 8.0

Step1:

Step2:

You absolutely must carefully read & understand percent questionsbefore you start the problem!!!!!!

You have two choices of where to start this problem (75 or 12)Only one will give you the correct answer!

07/27/12 lntaylor ©TOC

What number is 75 percent of 12?

Step3: Hint: Look for the number following the word “of”That number is the denominator“What number” becomes the numerator ( x )

Step4: Convert the percent to a fractionThis means the same as 75/100 and reducingConverting decimals to fractions is easy – the denominator is always 100

Step5: Solve for xIt helps to double check your work!

__12 x

3 (12)4

x = 36/4

of 12What number

x =

=

34

x = 9

912

= ¾ or 75%75%

Now you try

What number is twenty percent of 50?

07/26/12 lntaylor ©TOC

Step1:

Step2:

You absolutely must carefully read & understand percent questionsbefore you start the problem!!!!!!

You have two choices of where to start this problem (20 or 50)Only one will give you the correct answer!

07/27/12 lntaylor ©TOC

What number is twenty percent of 50?

Step3: Hint: Look for the number following the word “of”That number is the denominator“What number” becomes the numerator ( x )

Step4: Convert the percent to a fractionThis means the same as 20/100 and reducingConverting decimals to fractions is easy – the denominator is always 100

Step5: Solve for xIt helps to double check your work!

__50 x

1 (50)5

x = 50/5

of 50What number

x =

=

20100

x = 10

1050

= 1/5 or 20%20%

Now you try

What number is 34% of 200?

07/26/12 lntaylor ©TOC

Step1:

Step2:

You absolutely must carefully read & understand percent questionsbefore you start the problem!!!!!!

You have two choices of where to start this problem (34 or 200)Only one will give you the correct answer!

07/27/12 lntaylor ©TOC

What number is 34% of 200?

Step3: Hint: Look for the number following the word “of”That number is the denominator“What number” becomes the numerator ( x )

Step4: Convert the percent to a fractionThis means the same as 34/100 and you do not always have to reduce right hereConverting decimals to fractions is easy – the denominator is always 100

Step5: Solve for xIt helps to double check your work!

___200 x

34 (200)100

x = 34(2)

of 200What number

x =

=

34100

x = 68

68200 = 34/100 or 34%34%

07/27/12 lntaylor ©TOC

Change in Percent

Step1:

Step2:

You absolutely must carefully read & understand percent questionsbefore you start the problem!!!!!!

You have one choice of where to start this problem

07/27/12 lntaylor ©TOC

Tim starts with 120 balloons. He had 80 left after he gave some to Mary. What percent did he give away?

Step3: Hint: the parts of percent change are;StartFinishSome number(s) in between

Step4: The beginning is always the denominator (120)Make sure you understand what they wantIt could be what is left OR what was given away

Step5: Covert fraction to a decimal to a percent

80starts with 120

120 – 80 = 40

___120

40

give away

= =13

0.33 = 33%

Now you try

Mark had 90 apples. After he gave away 30 what percent did he have left?

07/26/12 lntaylor ©TOC

Step1:

Step2:

You absolutely must carefully read & understand percent questionsbefore you start the problem!!!!!!

You have one choice of where to start this problem

07/27/12 lntaylor ©TOC

Mark had 90 apples. After he gave away 30 what percent did he have left?

Step3: Hint: the parts of percent change are:StartSome number(s) in betweenFinish

Step4: The beginning is always the denominator (120)Make sure you understand what they wantIt could be what is left OR what was given away

Step5: Covert fraction to a decimal to a percent

30had 90

90 – 30 =

___ 90

60

gave away

= =23

0.667 = 66.7%

60

Now you try

Rick had half as many marbles as John. John had 500 marbles.They each gave away 125 marbles. What percent did they have left?

07/26/12 lntaylor ©TOC

Step1:

Step2:

You absolutely must carefully read & understand percent questionsbefore you start the problem!!!!!!

You have one choice of where to start this problem

07/27/12 lntaylor ©TOC

Rick had half as many marbles as John. John had 500 marbles.They each gave away 125 marbles. What percent did they have left?

Step3: Hint: the parts of percent change are:StartSome number(s) in betweenMore numbers in betweenEnding

Step4: The beginning is always the denominator (750)Make sure you understand what they wantIt could be what is left OR what was given away

Step5: Covert fraction to a decimal to a percent

They each gave away 125500

500 + ½ (500) = 500 + 250 = 750 Beginning

half as many marbles as John

125 + 125 = 250 gave away 750 beginning- 250 gave away 500 left

___750

500= =

23

0.667 = 66.7%

07/27/12 lntaylor ©TOC

Equivalents Table

07/27/12 lntaylor ©TOC

Fraction Decimal Percent

1/2

1/3

1/4

1/5

1/6

1/7

1/8

1/9

1/10

> 0.50

>

>

>

>

>

0.33

0.25

0.20

0.16

0.14

> 0.125

> 0.11

> 0.10

>

>

>

>

>

>

>

>

>

50%

33%

25%

20%

16%

14%

12.5%

11.0

10%

clear answers

07/27/12 lntaylor ©TOC

Practice

07/27/12 lntaylor ©TOC

Problem Answer

17 is what percent of 34?

What number is 30% of 50?

30 is 60% of what number?

27 is what percent of 3?

What number is 25% of 300?

21 is 70% of what number?

What is the decimal equivalent of 3/8?

What is the decimal equivalent of 5/9

What is the decimal equivalent of 4 and 3/5?

> 50%

>

>

>

>

>

15

50 (30/x = .6)

900%

75

30

> 0.375 (3 x 0.125)

> 0.555 (5 x .111)

> 4.6 ( 4 + 3(.2))

clear answers