1. Warm Up
Problem of the Day
Lesson Presentation
Lesson Quizzes

2. Warm Up 1. What is of 12? 6 2. What is of 100? 3. What is of 120? 50__ 6 1 2 __ 50 1 2 __ 60 1 4 __ 25 1 4 __
120

3. Problem of the Day
Your favorite uncle left one-fifth of his estate to each of his three children and the rest to his favorite charity. If his estate was worth $105,000, how much was given to charity?
$42,000

4. Learn to multiply fractions.

5. On average, people spend of their lives asleep. About 1 3 __
On average, people spend of their lives asleep. About
of the time they sleep, they dream. What fraction of
a lifetime does a person typically spend dreaming? 1 4 __ 1 4 __ 1 3 __
One way to find of is to make a model.
Find of . 1 4 __ 1 3 __ 1 4 __ 1 3 __ 1 12 __ • =

6. You can also multiply fractions without making a model.1 4 __ 1 3 __
_____
1 • 1
Multiply the numerators. • =
4 • 3
Multiply the denominators. 1 12 __
The answer is in simplest form. = 1 12 __
A person typically spends of his or her lifetime dreaming.
Notice that when you multiply two proper fractions, the product is less than either factor.

7. Multiply. Write each answer in simplest form.
Additional Example 1A: Multiplying Fractions
Multiply. Write each answer in simplest form. 1 4 __ 2 5 __ • 1 4 __ 2 5 __
_____
1 • 2 • =
Multiply numerators. Multiply denominators.
4 • 5 2 20 __ =
The GCF of 2 and 20 is 2. 1 10 __ =
The answer is in simplest form.

8. Multiply. Write each answer in simplest form.
Additional Example 1B: Multiplying Fractions
Multiply. Write each answer in simplest form. 5 7 __ 4 15 __ •
Use the GCF to simplify the fractions before multiplying. The greatest common factor of 5 and 15 is 5. 5 7 __ 1 4 15 __ 1 7 __ 4 3 __ • = • 3
_____
1 • 4
Multiply numerators. Multiply denominators. =
7 • 3 4 21 __ =
The answer is in simplest form.

9. Multiply. Write each answer in simplest form.
Additional Example 1C: Multiplying Fractions
Multiply. Write each answer in simplest form. 4 9 __ 6 10 __ • 4 9 __ 6 10 __
______
4 • 6 • =
Multiply numerators. Multiply denominators.
9 • 10 24 90 __ =
The GCF of 24 and 90 is 6. 4 15 __ =
The answer is in simplest form.

10. Multiply. Write each answer in simplest form.
Check It Out: Example 1A
Multiply. Write each answer in simplest form. 1 2 __ 3 6 __ • 1 2 __ 3 6 __
_____
1 • 3 • =
Multiply numerators. Multiply denominators.
2 • 6 3 12 __ =
The GCF of 3 and 12 is 3. 1 4 __
The answer is in simplest form. =

11. Multiply. Write each answer in simplest form.
Check It Out: Example 1B
Multiply. Write each answer in simplest form. 3 7 __ 5 9 __ •
Use the GCF to simplify the fractions before multiplying. The greatest common factor of 3 and 9 is 3. 3 7 __ 1 5 9 __ 1 7 __ 5 3 __ • = • 3
_____
1 • 5
Multiply numerators. Multiply denominators. =
7 • 3 5 21 __ =
The answer is in simplest form.

12. Multiply. Write each answer in simplest form.
Check It Out: Example 1C
Multiply. Write each answer in simplest form. 3 7 __ 5 15 __ • 3 7 __ 5 15 __
______
3 • 5 • =
Multiply numerators. Multiply denominators.
7 • 15 15
105
____ =
The GCF of 15 and 105 is 15. 1 7 __ =
The answer is in simplest form.

13. Additional Example 2A: Evaluating Fraction Expressions5 __
Evaluate the expression b • for each value of b.
Write each answer in simplest form. 1 3 __ 2 5 __
b =
b • 1 3 __ 1 3 __ 2 5 __ •
Substitute for b.
_____
1 • 2
3 • 5
Multiply. 2 15 __
The answer is in simplest form.

14. You can look for a common factor in a numerator and a denominator to determine whether you can simplify before multiplying.
Helpful Hint

15. Additional Example 2B: Evaluating Fraction Expressions3 8 __ 2 5 __
b • 3 8 __ 3 8 __ 2 5 __ •
Substitute for b. 1 3 8 __ 2 5 __ •
Use the GCF to simplify. 4
_____
3 • 1
4 • 5
Multiply. 3 20 __
The answer is in simplest form.

16. Additional Example 2C: Evaluating Fraction Expressions
b = 5 7 __ 2 5 __
b • 5 7 __ 2 5 __ 5 7 __ •
Substitute for b.
_____
5 • 2
7 • 5
Multiply. 10 35 __
The GCF of 10 and 35 is 5. 2 7 __
The answer is in simplest form.

17. Check It Out: Example 2A
Evaluate the expression c • for each value of c.
Write each answer in simplest form.
c = 1 4 __ 1 7 __ 1 4 __
c • 1 7 __ 1 4 __ 1 7 __ •
Substitute for c.
_____
1 • 1
7 • 4
Multiply. 1 28 __
The answer is in simplest form.

18. Check It Out: Example 2B c = 2 __ 7 2 __ Substitute for c. • 71 4 __
c • 2 7 __ 2 7 __ 1 4 __
Substitute for c. • 1 2 7 __ 1 4 __ •
Use the GCF to simplify. 2
_____
1 • 1
7 • 2
Multiply. 1 14 __
The answer is in simplest form.

19. Check It Out: Example 2C c = 4 7 __ 1 4 __ c • 4 7 __ 1 4 __ 4 7 __ •
Substitute for c.
_____
4 • 1
7 • 4
Multiply. 4 28 __
The GCF of 4 and 28 is 4. 1 7 __
The answer is in simplest form.

20. Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems

21. Multiply. Write each answer in simplest form. 1. 2.
Lesson Quiz
Multiply. Write each answer in simplest form.
Evaluate the expression x • for each value of x. Write the answer in simplest form.
3. x = x =
5. At a particular college of the students take a math class. Of these students, take basic algebra. What fraction of all students take basic algebra? 1 4 __ 3 5 __ 3 20 __ 3 10 __ 5 7 __ 3 14 __ • • 1 8 __ 4 5 __ 1 10 __ 1 8 __ 1 64 __ 2 5 __ 1 4 __ 1 10 __

22. Lesson Quiz for Student Response Systems
1. Multiply and identify the answer in simplest form.
A C.
B D.

23. Lesson Quiz for Student Response Systems
2. Multiply and identify the answer in simplest form.
A C.
B D.

24. Lesson Quiz for Student Response Systems
3. Evaluate the expression
and identify the answer in simplest form.
A C.
B D.

25. Lesson Quiz for Student Response Systems
4. Evaluate the expression
and identify the answer in simplest form.
A C. 1
B D. 5

26. Lesson Quiz for Student Response Systems
5. At a particular school of the students take chemistry class. Of these students, take organic chemistry. What fraction of all students take organic chemistry?
A C.
B D. 1