Percents 07/27/12lntaylor ©. Table of Contents Learning Objectives Straight Percent Change in...
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Transcript of 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