Transcript Percents, Fractions, & Decimals

Bell Work
Change each fraction to a decimal.
1) ½
2) 4/5
3) 2/3
4) 1/8
Learn to model percents and to write
percents as equivalent fractions and
decimals.
Learn to write decimals and fractions as
percents.
Vocabulary
Percent – A ratio of a number to a
hundred. The word percent
means “per hundred.”
The symbol % means “percent.”
Modeling Percents
Write the percent modeled by the grid.
shaded
_______
total
66 = 66%
___
100
Modeling Percents
Write the percent modeled by the grid.
A.
B.
shaded
_______
total
44 = 44%
___
100
shaded
_______
total
75 = 75%
___
100
Writing Percents as Fractions
Write 28% as a fraction in simplest form.
28
28% =
100
=
7
25
Write the percent as a fraction
with a denominator of 100.
Simplify.
7
So 28% can be written as 25 .
Fractions, Decimals, and
Percents
The students at Westview Middle School
are collecting cans of food for the local
food bank. Their goal is to collect 2,000
cans in one month. After 10 days, they
have 800 cans of food. What percent of
their goal have they reached?
Fractions, Decimals, and Percents
0
200
400
0
1
5
0
0.2
0
20%
600
800
2
5
1,000
1,200
1,400
1,600
1,800
2,000
3
5
4
5
0.4
0.6
0.8
1.0
40%
60%
80%
100%
5
5
800 2
The model shows that 800 out of 2,000 can be written as
, ,
2000 5
0.4, or 40%. The students have reached 40% of their goal.
Writing Decimals as Percents
Write 0.7 as a percent.
0.7 =
7
70
=
10 100
= 70%
Write the decimal as a fraction
with a denominator of 100.
Write the numerator with a
percent sign.
Writing Decimals as Percents
Write 0.93 as a percent.
0.93 = 93%
= 93%
Move the decimal point two
places to the right and add a
percent sign.
Writing Fractions as Decimals
and Percents
Write 5 as a percent.
8
5 =5÷8
8
= .625
= 62.5%
Use division to write the
fraction as a decimal.
Write the decimal as a percent.
Remember!
To divide 5 by 8, use long division and place a decimal point
followed by a zero after the 5.
.625
8 5.00
Ordering Rational Numbers
4
3
Order 17%, 0.25,
, 0.1, 5 , and 20% from
4
least to greatest.
Step 1: Write the numbers as decimals with the
same number of decimal places.
17% = 0.17
0.25 = 0.25
3 = 0.75
4
0.1 = 0.10
4 = 0.80
5
20% = 0.20
Ordering Rational Numbers
4
3
Order 17%, 0.25,
, 0.1, 5 , and 20% from
4
least to greatest.
Step 2: Compare the decimals.
17% = 0.17
0.25 = 0.25
3 = 0.75
4
0.1 = 0.10
4 = 0.80
5
20% = 0.20
Step 3: Re-order
numbers using original
format.
0.1, 17%, 20%, .25, 3 , 4
4 5
Real-World Application
Decide whether using pencil and paper, mental math, or a
calculator is most useful when solving the following
problem. Then solve.
If 27 out of 50 people have the newspaper delivered to their
home, what percent of these people have the newspaper
delivered to their home?
27
Think: 27 ÷ 50 divides evenly.
50
Using pencil and paper is the best method.
= 0.54
27 out of 50 =
Write the decimal as a percent.
= 54%
54% of the people have the newspaper delivered to their
home.