(7) Lesson 2.2

1. Course 2, Lesson 2-2
Find each number. Round to the nearest tenth if necessary.
1. 165% of 60
2. 233% of 75
3. 48% of 90
4. 20% of $365
5. 80% of 105
6. Tanya earns a perfect score 25% of the time that she performs
her gymnastics routine. If she performs 44 times in a season,
how many times will she NOT receive a perfect score?

2. Course 2, Lesson 2-2
ANSWERS
1. 99
2. 174.8
3. 43.2
4. $73
5. 84
6. 33

3. HOW can percent help you understand
situations involving money?
Ratios and Proportional Relationships
Course 2, Lesson 2-2

4. Ratios and Proportional Relationships
Course 2, Lesson 2-2 Common Core State Standards © Copyright 2010. National Governors Association Center for Best Practices and Council
of Chief State School Officers. All rights reserved.
• 7.RP.3
Use proportional relationships to solve multistep ratio and percent
problems.
• 7.EE.3
Solve multistep real-life and mathematical problems posed with
positive and negative rational numbers in any form (whole
numbers, fractions, and decimals), using tools strategically. Apply
properties of operations to calculate with numbers in any form;
convert between forms as appropriate; and assess the
reasonableness of answers using mental computation and
estimation strategies.

5. Ratios and Proportional Relationships
Course 2, Lesson 2-2 Common Core State Standards © Copyright 2010. National Governors Association Center for Best Practices and Council
of Chief State School Officers. All rights reserved.
Mathematical Practices
1 Make sense of problems and persevere in solving them.
3 Construct viable arguments and critique the reasoning of others.
4 Model with mathematics.
5 Use appropriate tools strategically.

6. How to:
• Estimate the percent of a number
• Find percents greater than 100 or less
than 1
Ratios and Proportional Relationships
Course 2, Lesson 2-2

7. 1
Need Another Example?
2
3
4
Step-by-Step Example
1. Jodi has paid 62% of the $500 she owes for her loan.
Estimate 62% of 500.
62% of 500 60% of 500 62% 60%
Multiply.300
So, 62% of 500 is about 300.

8. Answer
Need Another Example?
Estimate 61% of 440.
Sample answer: 61% ≈
and × 450 = 270

9. 1
Need Another Example?
2
3
Step-by-Step Example
2. Marita and four of her friends ordered a pizza that cost $14.72.
She is responsible for 20% of the bill. About how much money
will she need to pay?
Find 10% of $15.00.
10% of $15.00 = 0.1 $15.00
= $1.50 To multiply by 10%, move the
decimal point one place to the left.
Multiply.
20% of $15.00 is 2 times 10% of $15.00.
2 $1.50 = $3.00
So, Marita should pay about $3.00.

10. Answer
Need Another Example?
Melinda calculated that 40% of the coins in
her collection were minted before 1964. If
there are 715 coins in her collection, about
how many of them were minted before 1964?
Sample answer: about 280 coins; 715 ≈ 700
and 10% of 700 = 70 and 70 × 4 = 280

11. Need Another Example?
Step-by-Step Example
3. Estimate 122% of 50.
1
2
3
4
5
120% = 100% + 20%
122% is about 120%.
120% of 50 = 100% of 50 + 20% of 50
100% = 1 and 20% =
= 50 + 10 or 60 Simplify.
So, 122% of 50 is about 60.
= (1 50) + 50

12. Answer
Need Another Example?
Estimate 173% of 60.
Sample answer: 102;
100% of 60 = 60 and 70% of 60 = 42;
60 + 42 = 102

13. 1
Need Another Example?
2
3
4
5
Step-by-Step Example
4. There are 789 seventh grade students at Washington Middle
School. About % of the seventh grade students have traveled
overseas. What is the approximate number of seventh grade
students that have traveled overseas? Explain.
% is one fourth of 1%. 789 is about 800.
1% of 800 = 0.01 800 Write 1% as 0.01.
To multiply by 1%, move the decimal point
two places to the left.
= 8
One fourth of 8 is 8 or 2.
So, about 2 seventh grade students
have traveled overseas.

14. Answer
Need Another Example?
About % of Smithville’s 1,500 adult citizens are
attending the upcoming pop concert. What is the
approximate number of adults attending the
concert?
5 adults; Sample answer:
1% of 1,500 = 0.01 × 1500 = 15, × 15 = 5

15. 1
Need Another Example?
2
3
4
5
Step-by-Step Example
5. Last year, 639 students attended a summer camp.
Of those who attended this year, 0.5% also attended
summer camp last year. About how many students
attended the summer camp two years in a row?
0.5% is half of 1%.
1% of 639 = 0.01 639
6≈
So, 0.5% of 639 is about of 6 or 3.
About 3 students attended summer
camp 2 years in a row.

16. Answer
Need Another Example?
Last weekend, 96,081 people attended a
college football game. About 0.25% of them
were reporters from newspapers, television,
and radio stations. About how many reporters
were at the game?
about 240 reporters: Sample answer:
96,081 ≈ 96,000; 96,000 ×1% = 960
and 0.25 × 960 = × 960 or 240

17. How did what you learned
today help you answer the
HOW can percent help you understand
situations involving money?
Course 2, Lesson 2-2
Ratios and Proportional Relationships

18. How did what you learned
today help you answer the
HOW can percent help you understand
situations involving money?
Course 2, Lesson 2-2
Ratios and Proportional Relationships
Sample answers:
• You can use estimation strategies to estimate the
percent of a dollar amount.

19. Suppose another class
has 120% of the
students that are in our
class. About how many
students are in the
other class?
Ratios and Proportional RelationshipsRatios and Proportional Relationships
Course 2, Lesson 2-2