1

What are we going to do?

CFU

Students, you already know how to find equivalent fractions. Now, we will find equivalent fractions when adding fractions with like denominators.

Make Connection

We will add fractions with like denominators.

Learning Objective

Activate Prior Knowledge

Equivalent fractions are fractions that have the same value.

Find the equivalent fractions below.

1. 28

4

=22

2. 46

3

=22

2

23

numerator

denominator

Fraction

Common Core Standards 7.NS.1 - 7.NS.3 Prerequisite Skills Apply and extend previous understandings of addition, subtraction, multiplication, and division

of integers (AND other rational numbers); Students will reinforce skills learned in 6 th grade.

Name:________________

Monday 9.22.14

What are we going to do?

CFU

Students, you already know how to reduce fractions to the lowest terms. Now, we will use reducing fractions when subtracting fractions with like denominators.

Make Connection

Learning Objective

Activate Prior Knowledge

We will subtract fractions with like denominators.

1

Equivalent fractions are fractions that have the same value.

Find the equivalent fractions below.

1. 612÷

2=6

6

2. 412

3

=44

1

23

numerator

denominator

Fraction

Common Core Standards 7.NS.1 - 7.NS.3 Prerequisite Skills Apply and extend previous understandings of addition, subtraction, multiplication, and division

of integers (AND other rational numbers); Students will reinforce skills learned in 6 th grade.

4 + 26

+ =

Fractions with like denominators have the same number of equal parts.To add fractions, both fractions must have a like denominator.

• The sum of fractions must be reduced to the lowest terms.

Which addition problem has fractions with like denominators? How do you know?

A

B

CFU

Adding Fractions

Concept Development

Adolfo has four-twelfths of a pie. Carla has two-twelfths of a pie. How much of the pie do they have altogether?

23

numerator

denominator

Fraction

124

122+ =

12

25

15+

25

23+

Animated

Which of the following is an example of a reduced fraction? How do you know?

A

B

In your own words what is reducing a fraction? Reducing a fraction is _______.

CFU

Reducing Fractions

Concept Development (Clarification and CFU)

Equivalent fractions are fractions that have the same value.• Reducing a fraction is finding the equivalent fraction in the lowest

terms.

“Not in the lowest terms.”“In the lowest terms.”

23

numerator

denominator

Fraction

126 2

2 = 63 3

3 = 21

38

48

Concept Development

Fractions with like denominators have the same number of equal parts.To subtract fractions, both fractions must have a like denominator.• The difference of fractions must be reduced to the lowest terms.

Subtracting Fractions

Adolfo has eight-twelfths of a pie. If he eats two-twelfths of the pie how much of the pie is left?

- =

23

numerator

denominator

FractionAnimated

Which subtraction problem has fractions with like denominators? How do you know?

A

B

CFU

612

212-

412

46-

8 - 26128

122- =

12

Which of the following is an example of a reduced fraction? How do you know?

A

B

In your own words what is reducing a fraction? Reducing a fraction is _______.

CFU

Reducing Fractions

Concept Development (Clarification and CFU)

Equivalent fractions are fractions that have the same value.• Reducing a fraction is finding the equivalent fraction in the lowest

terms.

“Not in the lowest terms.”“In the lowest terms.”

23

numerator

denominator

Fraction

126 2

2 = 63 3

3 = 21

38

48

Add the fractions. (write) Keep the same denominator.Add the numerators.

Reduce the sum, if needed.Read the sum out loud. “___ plus ___ equals ___.”

Add fractions with like denominators.1

23

a

b How did I/you add the fractions?

CFU

1

Skill Development/Guided Practice

1. 2.

4.3.

To add fractions, both fractions must have a like denominator.• The sum of fractions must be reduced to the lowest terms. 2

3numerator

denominator

Fraction

25

+ 15

= 26

+ 36

=

18

+ 28

= 310

+ 410

=

35

56

38

710

Add the fractions. (write) Keep the same denominator.Add the numerators.

Reduce the sum, if needed.Read the sum out loud. “___ plus ___ equals ___.”

Add fractions with like denominators.1

23

a

b How did I/you add the fractions?How did I/you reduce the solution?

CFU

1

2

5.

7.

To add fractions, both fractions must have a like denominator.• The sum of fractions must be reduced to the lowest terms. 2

3numerator

denominator

Fraction

14

+ 14

=

18

+ 38

=

24

Skill Development/Guided Practice (continued)

6.

8.

26

+ 26

=

210

+ 410

=

22

12

= 46

22

23

=

48

44

12

= 610

22

35

=

Subtract the fractions. (write) Keep the same denominator.Subtract the numerators.

Reduce the difference, if needed.Read the difference out loud. “___ minus ___ equals ___.”

Subtract fractions with like denominators.1

23

a

b

Skill Development/Guided Practice

How did I/you subtract the fractions?

CFU

1

To subtract fractions, both fractions must have a like denominator.• The difference of fractions must be reduced to the lowest terms.

1. 2.

4.3.

23

numerator

denominator

Fraction

25

- 15

= 36

- 26

=

58

- 28

= 88

- 38

=

15

16

38

58

Subtract the fractions. (write) Keep the same denominator.Subtract the numerators.

Reduce the difference, if needed.Read the difference out loud. “___ minus ___ equals ___.”

Subtract fractions with like denominators.1

23

a

b

Skill Development/Guided Practice (continued)

How did I/you subtract the fractions?How did I/you reduce the difference?

CFU

1

2

To subtract fractions, both fractions must have a like denominator.• The difference of fractions must be reduced to the lowest terms. 2

3numerator

denominator

Fraction

5.

7.

34

- 14

=

78

- 38

=

24

6.

8.

56

- 36

=

910

- 310

=

22

12

= 26

22

13

=

48

44

12

= 610

22

35

=

Skill Development/Guided Practice (continued)

How did I/you determine what the question is asking?How did I/you determine the math concept required?How did I/you determine the relevant information?How did I/you solve and interpret the problem?How did I/you check the reasonableness of the answer?

CFU

2

1

3

4

5

38

58

+ 88

= 1= Juanito has 1 pound of nuts.

25

15

+ 35

=

Fareed spent of an hour on his math homework. He then spent of an hour on his English homework. How much time did he spend on his homework?

Fareed spent of an hour on his homework.

Juanito has of a pound of almonds. He also has of a pound of cashews. How many pounds of nuts does he have??

Skill Development/Guided Practice (continued)

How did I/you determine what the question is asking?How did I/you determine the math concept required?How did I/you determine the relevant information?How did I/you solve and interpret the problem?How did I/you check the reasonableness of the answer?

CFU

2

1

3

4

5

Jan has a piece of ribbon that is of an inch long. She cuts the ribbon into two pieces. One piece is of an inch long. How long is the other piece of ribbon?

Angela has of a pie. Her family eats of the pie. How much of the pie is left?

910

410

- 510

= 55

12

= The other piece of ribbon is an inch long.

58

38

- 28

= 22

14

=Angela has of the pie left.

Add the fractions. (write) Keep the same denominator.Add the numerators.

Reduce the sum, if needed.Read the sum out loud. “___ plus ___ equals ___.”

Add fractions with like denominators.1

23

a

b

What did you learn today about adding fractions with like denominators? (Pair-Share)Use words from the word bank.

Skill Closure

Access Common Core

Summary Closure

Arianna has added the fractions below. Mr. Babbage says that her answer is incorrect. Explain the mistake that Arianna made.

To add fractions, both fractions must have a like denominator.• The sum of fractions must be reduced to the lowest terms.

23

numerator

denominator

Fraction

1. 25

+ 15

= 35

2. 16

+ 26

= 36

33

12

=

58

+ 18

=

Word Bank

fractionnumerator

denominatorreduce

Arianna’s math is correct, but she did not reduce her answer. The correct answer is .

Subtract the fractions. (write) Keep the same denominator.Subtract the numerators.

Reduce the difference, if needed.Read the difference out loud. “___ minus ___ equals ___.”

Subtract fractions with like denominators.1

23

ab

Skill Closure

Access Common Core

Summary Closure

Ruby has subtracted the fractions below. Mr. Allen says that the answer is incorrect. Explain the mistake that Ruby made.

To subtract fractions, both fractions must have a like denominator.• The difference of fractions must be reduced to the lowest terms.

23

numerator

denominator

Fraction

What did you learn today about subtracting fractions with like denominators? (Pair-Share)Use words from the word bank.

Word Bank

fractionnumerator

denominatorreduce

710

- 210

=

1. 810

- 110

= 710

2. 512

- 112

= 412

44

13

=

Ruby’s math is correct, but he did not reduce his answer. The correct answer is .

Independent Practice (Add)

Add the fractions. (write) Keep the same denominator.Add the numerators.

Reduce the sum, if needed.Read the sum out loud. “___ plus ___ equals ___.”

Add fractions with like denominators.1

23

a

b

1.

3.

To add fractions, both fractions must have a like denominator.• The sum of fractions must be reduced to the lowest terms. 2

3numerator

denominator

Fraction

36

+ 16

=

710

+ 310

=

46

2. 18

+ 18

=22

23

= 28

22

14

=

1010

1010 1=

4. 110

+ 710

=810

22

45

=

Independent Practice (Subtract)

1.

3.

36

- 16

=

710

- 310

=

26

2. 78

- 58

=22

13

= 28

22

14

=

410

22

4. 4

10- 2

10=2

1022

15

=

Subtract the fractions. (write) Keep the same denominator.Subtract the numerators.

Reduce the difference, if needed.Read the difference out loud. “___ minus ___ equals ___.”

Subtract fractions with like denominators.1

23

a

b

To subtract fractions, both fractions must have a like denominator.• The difference of fractions must be reduced to the lowest terms. 2

3numerator

denominator

Fraction

25

=

CLASSWORK

Access Common Core

Which of the following fractions are correctly added and reduced?

Yes No

Yes No

Yes No

Yes No

1. 510

+ 310

= 810

2. 28

+ 48

=22

45

= 68

22

34

=

612

+ 312

912

=

512

+ 612

56

=

612

+ 312

34

=

312

+ 512

23

=

CLASSWORK

Access Common Core

Which of the following fractions are correctly subtracted and reduced?

1. 510

- 310

= 210

2. 48

- 28

=22

15

= 28

22

14

=

Yes No

Yes No

Yes No

Yes No

612

- 312

312

=

1112

- 612

50

=

612

- 312

34

=

512

- 312

16

=

CLASSWORK

Access Common Core

Bradley added the fractions below. Some of his answers are incorrect. Circle all the incorrect answers and write the correct solutions. Solutions should be in lowest terms.

1. 412

+ 312

= 712

2. 312

+ 512

= 812

44

23

=

38

+ 38

= 110

+ 210

= 36

+ 16

= 14

+ 24

=

412

+ 512

= 610

+ 210

= 36

+ 36

= 310

+ 510

=

14

+ 24

= 410

+ 610

= 18

+ 38

= 68

+ 18

=

CLASSWORK

Access Common Core

Bradley subtracted the fractions below. Some of his answers are incorrect. Circle all the incorrect answers and write the correct solutions. Solutions should be in lowest terms.

1. 412

- 312

= 112

2. 512

- 512

= 012

= 0

38

- 38

= 210

- 110

= 36

- 16

= 24

- 14

=

512

- 412

= 610

- 210

= 36

- 36

= 510

- 310

=

34

- 14

= 910

- 410

= 38

- 18

= 68

- 18

=

CLASSWORK

Access Common Core

Yes No

Yes No

1. 412

+ 412

= 812

2. 512

+ 112

=44

23

= 612

66

12

=

Yes No9

24

Yes No34

Choose Yes or No to show whether each choice

represents the sum of .5

124

12+

CLASSWORK

Access Common Core

1. 412

- 412

= 012

2. 512

- 112

== 0 412

44

13

=

Yes No

Yes No

Yes No36

Yes No60

Choose Yes or No to show whether each choice

represents the difference of .1012

412-