Lesson on percents

1. LET‛S GET IT STARTED
The following sentences (Lou Gehrig's farewell to baseball at Yankee stadium) contain exactly 100
letters. Read the sentences and complete the table below.
quot;I consider myself the luckiest man on the face of the earth. So I have been given a
bad break, but I have an awful lot to live for.quot;
Letter Number of times Fraction of 100 Percent
a 10 10/100 10%
b 4 4/100 4%
c 3 3/100 3%
d 2 2/100 2%
Questions:
1. How many times does the letter B appear? ______________________________
What percent of the total number of letters is this? ________________________
2. Which letter appears most often? ____________________________________
What percent of the total number of letters is this? ________________________
3. What is the sum of the percents for all the letters? ______________________
4. What percent of the letters are vowels? _______________________________
5. What percent of the letters match with the letters in your first name? _________
Title: Dec 6­11:15 PM (1 of 7)

2. TOPIC: Ratios and Proportions
AIM: How do we solve problems involving percentages?
NOTES
a part of a whole.
a) A percent is a way of expressing _________________________________________
a fraction and a decimal
b) A percent is always equivalent to ___________________________________________
Example: 25/100 0.25
25% = ________ = ________ 1/5 0.20
50/250 = _______= _______
Title: Dec 7­12:04 AM (2 of 7)

3. c) To solve the 3 types of problems dealing with percents we will use the following
,
proportion:
is %
_________ = __________
of 100
Ex1: What is 7% of 250?
Ex2: 30 is 15% of what number?
Ex3: 4 is what percent of 12?
Title: Dec 7­12:31 AM (3 of 7)

4. PRACTICE (in your binder)
1) Fill in for the percent form or decimal form:
a) 50% = _____ 0.5 b) 0.19 = _____ 19% c) 250% = ____ 2.5
2) Find 2.5% of 600 15
Answer
3) 125% of what number is 60? 48
Answer
4) 30 is what percent of 12? Answer
250
5) In a magazine, 30 pages of the 80 pages are devoted to sports. 37.5
Answer
What percent of the magazine is devoted to sports?
6) Willy makes 6% of his total sales. Willy made $480,000. 28800
Answer
How much did he sell?
Title: Dec 7­12:39 AM (4 of 7)

5. SUMMARY
In your own words, explain the connection between percentages and proportions.
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Title: Dec 7­1:24 AM (5 of 7)

6. HW38: P387#3, 11 P388# 18, 23, 26, 27, 29, 33
Title: Dec 7­12:40 AM (6 of 7)

7. Title: Jan 29­5:12 PM (7 of 7)