Transcript Slide 1

6-1 Introduction to Percents
California
Standards
Preparation for
NS1.4 Calculate
given percentages of quantities and solve
problems involving discounts at sales, interest
earned, and tips.
Also covered:
NS2.4
Holt CA Course 1
6-1 Introduction to Percents
Vocabulary
percent
Holt CA Course 1
6-1 Introduction to Percents
A percent is a ratio of a number to 100. The
symbol % is used to indicate a percent.
6
= 6%
100
Reading Math
The word percent means “per hundred.”
So 6% means “6 out of 100.”
Holt CA Course 1
6-1 Introduction to Percents
Teacher Example 1: Modeling Percents
Write the percent modeled by each grid.
A.
B.
shaded
_______
total
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32 = 32%
___
100
shaded
_______
total
66 = 66%
___
100
6-1 Introduction to Percents
Student Practice 1:
Write the percent modeled by each grid.
A.
B.
shaded
_______
total
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44 = 44%
___
100
shaded
_______
total
75 = 75%
___
100
6-1 Introduction to Percents
Teacher Example 2: 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.
So 28% can be written as
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7 .
25
6-1 Introduction to Percents
Student Practice 2:
Write 90% as a fraction in simplest form.
90
90% =
100
=
9
10
Write the percent as a fraction
with a denominator of 100.
Simplify.
9
So 90% can be written as 10 .
Holt CA Course 1
6-1 Introduction to Percents
Teacher Example 3: Writing Percents as Decimals
Write 17% as a decimal.
Method 1
Use pencil and paper.
Write the percent as a fraction with a
17% = 17
100
denominator of 100.
= 0.17 Divide 17 by 100.
Method 2
Use mental math.
17% = 0.17
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Move the decimal point two places
to the left.
6-1 Introduction to Percents
Student Practice 2:
Write 24% as a decimal.
Method 1
Use pencil and paper.
24% = 24
100
Write the percent as a fraction with a
denominator of 100.
= 0.24 Divide 24 by 100.
Method 2
Use mental math.
24% = 0.24
Holt CA Course 1
Move the decimal point two places
to the left.
6-1 Introduction to Percents
Lesson Quiz
1. Write the percent modeled by the grid.
36%
2. Write 92% as a fraction in simplest form.
23
25
3. Write 16.4% as a decimal.
0.164
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