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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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To change a fraction into a decimal, you divide the
NUMERATOR by the DENOMINATOR.
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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To change a fraction into a decimal, you divide the
NUMERATOR by the DENOMINATOR.
Write each fraction or mixed number as a decimal.
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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To change a fraction into a decimal, you divide the
NUMERATOR by the DENOMINATOR.
Write each fraction or mixed number as a decimal.
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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To change a fraction into a decimal, you divide the
NUMERATOR by the DENOMINATOR.
Write each fraction or mixed number as a decimal.
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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Fractions to Percents
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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Fractions to Percents
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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Fractions to Percents
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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Copy and complete this chart
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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Copy and complete this chart
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
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