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

2. Warm Up
Multiply. 7 9 3 6 7 18 1. 9 8 6 5 27 20 7
or 1 2. 2 77 5
or 15 1 5 3. 2 7 1 2 1 4 25 8
or 3 1 4. 2
· 1

3. Problem of the Day
The Jeffers family is putting in a new fence around their yard. The yard is in the shape of a square. If they put nine fence posts on each side of the square, how many posts will be used? 32

4. Learn to divide fractions and mixed numbers.

5. Vocabulary
reciprocal

6. Dividing by a number is the same as multiplying by its reciprocal.
Reciprocals can help you divide by fractions. Two numbers are reciprocals or multiplicative inverses if their product is 1. The reciprocal of is 3 because 1 3 1 3
· 3 = 1.
Dividing by a number is the same as multiplying by its reciprocal.
2 ÷ 1 3
= 2 · 3 = 6

7. Additional Example 1: Dividing Fractions
Divide. Write each answer in simplest form. 3 7 2 5 ÷ A. 3 7 2 5 3 7 5 2 2 5 ÷ =
Multiply by the reciprocal of . 3 7 5 = 2 15 14 14 1 =
or 1 3 8 B. ÷ 12 3 8 1 3 8
Multiply by the reciprocal of 12. ÷ 12 = 12 1 3 8 1
Simplify. = 12 4 1 = 32

8. ÷ Check It Out: Example 1 Divide. Write each answer in simplest form.3 5 1 2 ÷ A. 3 5 1 2 3 5 2 1 1 2 ÷ =
Multiply by the reciprocal of . 3 5 2 = 1 6 5 1 =
or 1 5 3 4 B. ÷ 3 3 4 1 3 4
Multiply by the reciprocal of 3. ÷ 3 = 3 1 3 4 1
Simplify. = 3 1 1 = 4

9. Additional Example 2: Dividing Mixed Numbers
Divide. Write each answer in simplest form. 2 3 1 4 A. 5 ÷ 1
Write mixed numbers as improper
fractions. 2 3 17 3 5 4 5 1 4 ÷ 1 = ÷ 17 3 4 5 5 4 =
Multiply by the reciprocal of . 68 15 =
or 4 8 15 3 4 1 2 B. ÷ 2
Write 2 as an improper fraction. 1 2 3 4 1 2 3 4 5 2 ÷ 2 = ÷ 5 2 3 4 2 5 =
Multiply by the reciprocal of . 1 3 2
Simplify. = 4 5 2 3 10 =

10. Additional Example 2: Dividing Mixed Numbers
Divide. Write the answer in simplest form. 2 3 13 27 C. 8 ÷ 8 2 3 ÷ 13 27 = 26 3 ÷ 13 27
Write 8 as an improper fraction. 2 3 = 26 3 27 13
Multiply by the reciprocal of . 13 27 2 9 = 26 3 27 13 1 1 = 18 1
or 18

11. Check It Out: Example 2 Divide. Write each answer in simplest form. 23 1 2 A. 3 ÷ 1
Write mixed numbers as improper
fractions. 2 3 11 3 3 2 3 1 2 ÷ 1 = ÷ 11 3 2 3 3 2 =
Multiply by the reciprocal of . 22 9 =
or 2 4 9 3 5 2 5 B. ÷ 1
Write 1 as an improper fraction. 2 5 3 5 2 5 3 5 7 5 ÷ 1 = ÷ 7 5 3 5 5 7 =
Multiply by the reciprocal of . 1 3 5
Simplify. = 5 7 1 3 7 =

12. Check It Out: Example 2 Divide. Write the answer in simplest form. 1 518 5 C. 7 ÷ 7 1 5 ÷ 18 = 36 5 ÷ 18
Write 7 as an improper fraction. 1 5 = 36 5 5_ 18
Multiply by the reciprocal of 18 5 2 1 = 36 5 18 1 1 = 2 1
or 2

13. Additional Example 3: Social Studies Application
The life span of a golden dollar coin is 30 years, while
paper currency lasts an average of 1 years. How many 1 2
times longer will the golden dollar stay in circulation? 1 2 30 1 3 2
30 ÷ 1 = ÷
Write the number as an improper fraction. 30 1 2 3 3 2 =
Multiply by the reciprocal of . 10 30 2 =
Simplify. 1 3 1 20 1 =
or 20
The golden dollar will stay in circulation about
20 times longer than paper currency.

14. The queen ant will live 7 times longer than the worker ant.
Check It Out: Example 3
The average life of a queen ant is approximately 3 years.
The life span of a worker ant is year. How many 3 7
times longer will the queen ant live? 3 7 3 1 3 7
3 ÷ = ÷
Write the number as an improper fraction. 3 1 7 3 3 7 =
Multiply by the reciprocal of . 1 3 7 =
Simplify. 1 3 1 7 1 =
or 7
The queen ant will live 7 times longer than the
worker ant.

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

16. Divide. Write each answer in simplest form.
Lesson Quiz
Divide. Write each answer in simplest form. 4 5 1.
8 ÷ 10 5 9 4 9 40 or 2. 1 8 ÷ 1 10 3. 3 5 ÷ 6 3 4. 2 1 ÷ 7 35 44 1 4 3 4
5. There are 5
yards of silk in a roll. If it takes
of a yard to make one designer scarf, how many
scarves can be made from the roll? 7

17. Lesson Quiz for Student Response Systems
1. Divide. Write your answer in simplest form.
10 ÷
A. 6
B. 18
C. 12
D. 24
5 6

18. Lesson Quiz for Student Response Systems
2. Divide. Write your answer in simplest form. ÷
A or 4 C.
B. or 2 D.
4 7
1 5
20 5
4 35
20 7
6 7
3 35

19. Lesson Quiz for Student Response Systems
3. Divide. Write your answer in simplest form.
÷ 15
A or 9 C.
B D. or
5 8
75 8
3 8
1 24
3 15
1 5

20. Lesson Quiz for Student Response Systems
4. Multiply. Write your answer in simplest form.
3 ÷ 5
A C. or 1
B D. 27
1 3
2 5
50 81
81 50
31 50
23 27

21. Lesson Quiz for Student Response Systems
1 2
5. A blacksmith has 6 pounds of iron with
him. If it takes of a pound to make one
lock, how many locks can he make from the iron?
A. 9 locks
B. 11 locks
C. 12 locks
D. 13 locks
1 2