fractions decimals and percents (1)

8/10/2019 Fractions Decimals and Percents (1)

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FRACTIONS,DECIMALS &

PERCENTS

OH MY!


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OH MY! The table shows the heights of

the ten tallest buildings in Dallas.Dallas Tallest Buildings

Building Height (ft)

Bank of America Plaza 921

Renaissance Tower 886

Bank One Center 787

JP Morgan Chase Tower 738

Fountain Place 721

Trammell Crow Center 686

1700 Pacific Avenue 655

Thanksgiving Tower 645

Energy Plaza 629

Elm Place 625

1. What fraction of the

buildings are between

600 and 900 feet tall?

2. Write this fraction

using words.

3. Write this fraction as a

decimal.

1. 9 out of 10, which is 9/102. Nine-tenths

3. 0.9


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To change a fraction into a decimal, you divide the

NUMERATOR by the DENOMINATOR.

For example, to change into a decimal, you would

divide the 3 by the 4.4

3

344

3 0.34

0. 7

-2 8

20

5

-2 00

75.04

3

This is called a TERMINATING DECIMAL.

(it comes to an end, as in terminate a game!)


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Write each fraction or mixed number as a decimal.

20

70.720

0.3

-6 0

1 00

5

-1 0 0

0

35.0

20

7

This is called a TERMINATING DECIMAL.

(it comes to an end, as in terminate a game!)

Example 1:


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4

35 75.5

4

35

Memorizing some conversions like these will make things a lot

EASIER!

Example 2: We already

know that =

0.75

= 0.25 = 0.50 = 0.75

(one quarter) (half of a dollar) (three quarters)


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8

32 375.2

8

32

Example 3:0.38

0.3

-2 4

6 0

7

- 5 6

4 0

5

- 4 0

0


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3

1

3.0...333.0 Example 4:

0.13

0.3

- 9

1 0

3

- 9

1 0

3..

- 9

1

This is called a REPEATING DECIMAL.

(a pattern in the digits repeats forever!)


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You can use BAR NOTATION to indicate that a number

repeats forever. A bar is written over the digit(s) that repeat.

Example 5: Write 7/9 as a decimal.

0.79

0.7

-6 3

7 0

7

- 6 3

7 0- 6 3

7

77.0...777.0

9

7


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To change a decimal into a fraction, you place the

decimal number over the correct pace value position

as a fraction ( #/10 #/100 #/1000)

For example, to change 0.25into a fraction, you

would place 25 over a denominator of 100 since it isread twenty-five hundredths.

25/100 = 1/4


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Copy and complete this chart

Decimal Fraction

1) 0.7

2) 0.08

3) 0.42

4) 0.04

5) 0.71

6) 0.07


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Classwork

Title: Glencoe Pg. 247 # 21-35

Advanced: Glencoe Pg. 247 # 27-36, 38-42


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How to change percentages into

fractions and decimals

A percentage is a special

fraction.

The %says,per hundred.

For example,47%, is simply anotherway of writing thefraction47/100


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Fractions to Percents

A ratio is a comparison of 2 quantities by

division. Fractions are ratios!

can be written as 34:100 in ratio form.

When a ratio compares a number to 100, it

can be written as a percent.

100

34


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Ex 1: Annie answered 90 out of 100 questions

correctly.

100

90Since the fraction

already has a

denominator of 100,

you automatically

have thepercentage!

%90


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Ex 2: On average, 50.5 out of 100 students

own a pet.

100

5.50Since the fraction

already has a

denominator of 100,

you automatically

have thepercentage!

%5.50


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20

3

Find an equivalentfraction that has a

denominator of 100

%15

20

3

100

x

x5

x5

100

15

Ex 3: Write as a percent.


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Try These

20

17

%85100x

x5

x5

100

85

53 %60100

x

x20

x20

10060

25

2

%8100

x

x4

x4

100

8


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You can almost see the 100 in the

percentage sign

The 1The

zeros

Percentage Fraction

7% 7/100

19% 19/10083% 83/100

Etc.


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24% = 24/100 12/50 6/25

So to write a percentage as a

fraction, you simply put it

over 100 like this:

Yes, but remember to

write the fraction in its

simplest form

24% = 24/100


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Percentage Fraction Percentage Fraction

1. 23% 23/100 7. 80%2. 24% 8. 84%

3. 55% 9. 12%

4. 20% 1/5 10. 48%5. 17% 11. 71%

6. 78% 12. 36%


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Classwork

Glencoe Pg. 252 # 13-29, 34-36

Advanced: Glencoe Pg. 252 # 10-33 even, 37-

40, 42, 43


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So, to change a percentage into a

decimal, you always divide by100

For example, 35% as a fraction is 35/100 so tochange this into a decimal, you divide 35 by

100

35% 0.35100


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To change decimal into a

percentageDecimal Percentage

To change a decimal into apercentage, you X by 100

0.23 23%X 100


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You Should Know

A a percentage is aspecial fraction.

23% = 23/100

Percentage

to adecimal

100

Decimal to

apercentage

X 100


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Percentage Decimal Decimal Percentage

1. 27% 7. 0.87

2. 2% 8. 0.08

3. 55% 9. 0.42

4. 5% 10. 0.045. 17% 11. 0.71

6. 98% 12. 0.07

fractions decimals and percents (1)

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