Do Now
Choose the best unit price. To receive
credit you must show that you have
worked out both prices.
A.
B.
A 32-oz. bottle of apple juice for
$2.50 or
A 48 oz bottle of apple juice for
$3.48.
Chapter 7
Lesson 5
Fractions, Decimals, and
Percents
Objective: Write percents
as fractions and vice versa
The graph shows the results of a survey in which teens were asked to
name the most important invention of the 20th century.
1. What percent of the
teens said that the
personal computer was
the most important
invention?
32%
2. How is this percent
written as a ratio?
Percent of Teens
35
30
25
20
15
10
5
0
TV
Wireless
Phone
32
32:100 or
3. Simplify the ratio.
8
25
100
Pacemaker
Personal
Computer
Recall
How do you write a percent as a
fraction?
Put the percent over 100 then simplify
Example
32
32% =
100
8
=
25
To change percents with decimals
into fractions in simplest form
1.
Write the percent as a fraction with
a denominator of 100.
2.
To eliminate the decimal point add
the amount of zeroes there are
decimal places.
3. Simplify.
Percents with decimals to fractions
Examples.
1. 16.8%
2. 16.8
100
3.
168
1000
4.
21
25
Write each percent as a fraction in
simplest form.
6.2%
28.75%
28.75
6.2
100
100
62
2875
1000
10,000
31
500
23
80
To change percents with mixed numbers into
fractions in simplest form
1.
Change the mixed number into an
improper fraction
2.
Divide by 100 (you have to multiply by
the reciprocal when dividing fractions)
3.
Cross cancel and simplify
Percents with mixed numbers to
fractions
8 ⅓%
25
3
25
3
25
÷
100
1
X
3
100
1
12
81 ¼%
You try it!
78 ¾%
325
4
325 X 1
4
100
315
4
315
4
13
16
63
80
X
1
100
To write a fraction as a percent
1.
Create a proportion
Write each fraction as a percent.
Round to the nearest hundredth if
necessary.
4
15
7
8
7
8
=
87.5%
n
100
4
15
=
26.67%
n
100
Write each percent as a fraction in
simplest form.
1.
13.5%
27
200
2. 18.75%
3
16
3. 66 2/3%
2/3
4. 57 ½%
23/40