Math 8 Foundations
Name: ___________________
Date: ______________
Chapter 4- Understanding Percent
Sections 4.2 Fractions, Decimals, and Percents
4.2 Warm Up
1.
2.
numerator ÷ denominator
Change each fraction to a decimal.
a)
2
=
10
b)
15
=
20
c)
75
=
100
d)
3
=
5
Multiply by 100.
Change each decimal to a percent.
a) 0.12 =
%
b) 0.45 =
c) 0.6 =
3.
d) 3.14 =
Write each percent as a fraction of 100.
a) 30% =
4.
b) 9% =
100
100
Use equivalent fractions to find the missing number.
a)
2
=
25
b)
100
× ______
5.
%
14
=
20
100
× ______
In what place is the last digit? Use the place value chart to help you.
Tens
Ones
0
.
.
Tenths
3
Hundredths
5
a) 0.35
b) 0.7
c) 0.002
d) 45.891
Thousandths
Example 1: Convert Fractions to Decimals and Percents
Change each fraction to a decimal and a percent.
1
20
a)
Method 1: Use a Hundred Grid
Percent means out of 100.
This is
squares are shaded.
, which is
100
% or 0.05.
Method 2: Divide
To find a decimal, divide the numerator by the denominator.
1 ÷ 20 =
To change the decimal to a percent, multiply by 100.
Method 3: Make an Equivalent Fraction
Make an equivalent fraction out of 100.
×5
1
=
20
100
=
× 100 =
%
%
×5
So,
1
=
20
% or 0.
.
1 ÷ 20 = 0._____
71
200
Method 1: Divide
b)
Method 2: Make an Equivalent Fraction
To find a decimal, divide the numerator by
the denominator.
71 ÷ 200 =
To change the decimal to a percent,
multiply by 100.
× 100 =
%
So,
c)
71
=
200
5
4
% or 0.
Make an equivalent fraction out of 100.
÷2
71
=
200
.
÷2
100
=
%
Example 2: Convert Decimals to Percents and Fractions
Change each decimal to a percent and a fraction.
a) 3.26
Shade 3 full hundred grids plus 26 squares.
3.26 =
Use place values to show 3.26 as a fraction.
26
The 6 is in the hundredth place, so the fraction is 3
.
100
326
= 326%
100
Ones Decimal Tenths Hundredths
3
2
6
.
÷2
Write in lowest terms:
26
=
100
50
. So, 3.26 is 326% or 3
.
50
÷2
b) 0.125
Multiply by 100 to write 0.125 as a percent: 0.125 × 100 =
The 5 is in the thousandth place, so the fraction is
%.
125
.
1000
Write in lowest terms:
÷5
125
=
1000
÷5
200
÷5
200
=
40
÷5
So, 0.125 is 12.5% or
÷5
40
=
8
÷5
.
8
Change each decimal to a percent and a fraction. Write the fraction in lowest terms.
a) 0.56
Percent:
Fraction:
b) 3.98
Percent:
%
Fraction:
So, 3.98 is
or
%.
Example 3: Convert Percents to Fractions and Decimals
Change each percent to a fraction in lowest terms and a decimal.
a)
160%
Write the percent as a fraction out of 100.
Write your answer
in lowest terms.
÷ 10
100
=
÷2
10
10
÷ 10
=
5
÷2
To find the decimal, divide the numerator by the denominator.
160
=
100
b)
÷
=
0.35
0.35% = 100
0.35%
Divide by 100 to find the decimal: 0.35 ÷ 100 =
The 5 is in the ten thousandths place, so 0.0035 =
÷5
× 100
0.35
35
=
100 10 000
10 000
× 100
Assignment pg 135 # 4 – 6, 9, 11, 14, 16
=
35
.