Lesson 3.3.1 – Dividing Fractions and Mixed Numbers

Lesson 3.3.1 – Dividing Fractions and Mixed Numbers
Teacher Lesson Plan
Lesson:
3.3.1 – Supplement
Dividing Fractions and Mixed Numbers
CC Standards
7.NS.2
Apply and extend previous understandings of multiplication and division and of fractions to
multiply and divide rational numbers.
b. Understand that integers can be divided, provided that the divisor is not zero, and every quotient
of integers (with non-zero divisor) is a rational number. If p and q are integers, then
-(p/q) = (-p)/q = p/(-q). Interpret quotients of rational numbers by describing real-world contexts.
Objective
Students will review how to divide fractions and mixed numbers. This was a skill taught in 6 th grade and will
get them ready for the rules for dividing signed numbers.
Mathematical Practices
#1 Make sense of problems and persevere in solving them.
#8 Look for and express regularity in repeated reasoning.
Teacher Input
Bellwork:
Homework:
Introduction:
Lesson:
Review bellwork.
Review important problems assigned the previous night.
The 3.3.1 PowerPoint starts with a recap of what students have learned in chapter two and
chapter 3. Then the lesson proceeds to a review of dividing fractions and mixed numbers
which was covered in 6th grade. This will get them ready to dividing signed number using
the rules.
Teach as directed in the PowerPoint. Students should follow along in their notes.
Practice
Classwork:
Extra Practice:
Homework:
Page 4
Page 5 (dividing decimals by decimals)
Page 6
Closure
1. What is our strategy for dividing fractions? Keep it, Change it, Flip it (KCF)
2
πŸ‘
2. What is the reciprocal of ?
3
𝟐
3. How would you change the following division problem to a multiplication problem?
1
2
𝟏
πŸ‘
÷ 3=
× πŸ
2
𝟐
5
6
÷
4
5
=
πŸ“
πŸ”
×
πŸ“
πŸ’
4. What MUST you do to all mixed numbers when multiplying and dividing? Turn to improper fractions
1|Page
Lesson 3.3.1 – Dividing Fractions and Mixed Numbers
Student Notes
Section 1: Vocabulary
Reciprocals – Two numbers are reciprocals if their product = 1.
To get the reciprocal of a fraction, just flip it over.
The reciprocal of
πŸ‘
πŸ’
is…………
What is the reciprocal of
5
8
πŸ’
3
πŸ‘
4
x
4
3
=
12
12
=
1
? ________
Section 2: Strategy for Dividing Fractions and Mixed Numbers
To divide by a fraction, you multiply by its reciprocal! Strategy: Keep, Change, Flip (KCF)
Step 1:
Convert mixed numbers
to improper fractions.
πŸ‘
𝟐
Step 2: KEEP IT!
Keep the first fraction
the same.
πŸ‘
Step 3: CHANGE IT!
Change ÷ to ×.
πŸ‘
Step 4: FLIP IT!
Flip the numerator and
denominator.
πŸ‘
Step 5:
Multiply as usual.
πŸ‘
÷
πŸπŸ‘
πŸ’
There are no improper fractions.
𝟐
𝟐
𝟐
𝟐
×
×
×
πŸ’
πŸπŸ‘
πŸ’
πŸπŸ‘
=
𝟏𝟐
πŸπŸ”
Simplify
πŸ”
πŸπŸ‘
2|Page
Lesson 3.3.1 – Dividing Fractions and Mixed Numbers
Section 3: Guided and Independent Practice
Guided Practice #1
You Try #1
10 1
÷ =
8 6
11 4
÷ =
10 5
Guided Practice #2
You Try #2
4 8
÷ =
11 3
8 4
÷ =
9 3
Guided Practice #3
You Try #3
3
7
3 ÷1 =
8
8
1
3
7 ÷2 =
5
5
Guided Practice #4
You Try #4
3
1
4 ÷1 =
7
2
3
13
7
÷1
=
16
16
3|Page
Lesson 3.3.1 – Dividing Fractions and Mixed Numbers
Classwork
4|Page
Lesson 3.3.1 – Dividing Fractions and Mixed Numbers
Extra Practice
5|Page
Lesson 3.3.1 – Dividing Fractions and Mixed Numbers
Homework
Name: ____________________________
Period: _________ Date: ________
Divide the following fractions. Write each answer in simplest form!
1.
2.
K C F
𝟏
𝟏
÷ =
πŸ’
πŸ“
πŸ”
πŸ‘
πŸ“
÷ =
πŸ–
3.
πŸ– ÷
4.
𝟏
5.
πŸ“
πŸ—
πŸ“
πŸπŸ”
𝟏
πŸ‘
7.
πŸ‘
πŸ’
πŸ“
πŸ“
πŸ‘
=
÷𝟐
÷
6.
𝟐
𝟏
𝟐
𝟏
πŸ‘
=
=
𝟏
÷ 𝟏 =
πŸ“
𝟐
÷ 𝟐 =
πŸ“
1
8. You want to bike 16 miles in 1 hour. What should your average speed per hour be to
3
achieve this goal?
πŸ‘
9. Suzanne has of a cake left after a party. If she divides the leftover cake equally so that 5
πŸ’
people can take some of it home, what fraction of the original cake will each person
receive?
6|Page
Lesson 3.3.1 – Dividing Fractions and Mixed Numbers
7|Page
Lesson 3.3.1 – Dividing Fractions and Mixed Numbers
Student Notes
Section 1: Vocabulary
Reciprocals – Two numbers are reciprocals if their product = 1.
To get the reciprocal of a fraction, just flip it over.
The reciprocal of
πŸ‘
πŸ’
is…………
What is the reciprocal of
5
8
πŸ’
3
πŸ‘
4
x
4
3
=
12
12
=
1
? ________
Section 2: Strategy for Dividing Fractions and Mixed Numbers
To divide by a fraction, you multiply by its reciprocal! Strategy: Keep, Change, Flip (KCF)
Step 1:
Convert mixed numbers
to improper fractions.
πŸ‘
𝟐
Step 2: KEEP IT!
Keep the first fraction
the same.
πŸ‘
Step 3: CHANGE IT!
Change ÷ to ×.
πŸ‘
Step 4: FLIP IT!
Flip the numerator and
denominator.
πŸ‘
Step 5:
Multiply as usual.
πŸ‘
÷
πŸπŸ‘
πŸ’
There are no improper fractions.
𝟐
𝟐
𝟐
𝟐
×
×
×
πŸ’
πŸπŸ‘
πŸ’
πŸπŸ‘
=
𝟏𝟐
πŸπŸ”
Simplify
πŸ”
πŸπŸ‘
8|Page
Lesson 3.3.1 – Dividing Fractions and Mixed Numbers
Section 3: Guided and Independent Practice
Guided Practice #1
You Try #1
10 1
𝟏
÷ = πŸ•
8 6
𝟐
11 4
πŸ‘
÷ = 𝟏
10 5
πŸ–
Guided Practice #2
You Try #2
4 8
πŸ‘
÷ =
11 3
𝟐𝟐
8 4
𝟐
÷ =
9 3
πŸ‘
Guided Practice #3
You Try #3
3
7
πŸ’
3 ÷1 =𝟏
8
8
πŸ“
1
3
𝟏𝟎
7 ÷2 =𝟐
5
5
πŸπŸ‘
Guided Practice #4
You Try #4
3
1
𝟐𝟎
4 ÷1 =𝟐
7
2
𝟐𝟏
3
13
7
πŸπŸ“
÷1
=𝟐
16
16
πŸπŸ‘
9|Page
Lesson 3.3.1 – Dividing Fractions and Mixed Numbers
Classwork
Answer Key
10 | P a g e
Lesson 3.3.1 – Dividing Fractions and Mixed Numbers
11 | P a g e
Lesson 3.3.1 – Dividing Fractions and Mixed Numbers
Name: ____________________________
Period: _________ Date: ________
Homework
Answer Key
Divide the following fractions. Write each answer in simplest form!
1.
2.
K C F
𝟏
𝟏
÷ =
πŸ’
πŸ‘
πŸ“
4
πŸ“
5
πŸ–
6
÷ =
πŸ”
3.
πŸ– ÷
4.
𝟏
5.
1
πŸ“
πŸ—
πŸ“
πŸπŸ”
𝟐
πŸ‘
÷𝟐
÷
𝟏
𝟐
𝟏
πŸ‘
1
14
=
9
5
=
16
πŸ‘
𝟏
8
πŸ“
πŸ“
5
6.
1 ÷ 𝟏 =
7.
πŸ‘
πŸ’
πŸ“
×
8
=
𝟐
19
πŸ“
5
÷ 𝟐 =
3
×
1
8
3
2
7
÷
3
2
×
÷
1
6
𝟏
12
5
𝟏
πŸ‘
𝟏𝟐
=
14
=
9
×
3
7
𝟐
=
πŸ‘
πŸ“
=
πŸ–
8
=
5
÷
πŸ’
=
5
×
πŸ‘
=
5
×
19
=
5
5
6
×
𝟏
=
5
12
𝟏
=
𝟏
πŸ‘
πŸ•
𝟏𝟐
1
8. You want to bike 16 miles in 1 hour. What should your average speed per hour be to
3
achieve this goal?
1
16
4
16
3
16 ÷ 1 =
÷ =
× =
12 miles per hour
3
1
3
1
4
πŸ‘
9. Suzanne has of a cake left after a party. If she divides the leftover cake equally so that
πŸ’
5 people can take some of it home, what fraction of the original cake will each person
receive?
3
3
1
πŸ‘
÷ 5=
×
=
4
4
5
𝟐𝟎
12 | P a g e