M A T H E M A T I C S

4

Modified In-School Off-School Approach Modules (MISOSA)

Distance Education for Elementary Schools

SELF-INSTRUCTIONAL MATERIALS

ADDITION OF SIMILAR FRACTIONS

Department of Education

BUREAU OF ELEMENTARY EDUCATION 2nd Floor Bonifacio Building DepEd Complex, Meralco Avenue Pasig City

Revised 2010 by the Learning Resource Management and Development System (LRMDS),

DepEd - Division of Negros Occidental under the Strengthening the Implementation of Basic Education

in Selected Provinces in the Visayas (STRIVE).

This edition has been revised with permission for online distribution through the Learning Resource Management Development System (LRMDS) Portal (http://lrmds.deped.gov.ph/) under Project STRIVE for BESRA, a project supported by AusAID.

Section 9 of Presidential Decree No. 49 provides: “No copyright shall subsist in any work of the Government of the Republic of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit.” This material was originally produced by the Bureau of Elementary Education of the Department of Education, Republic of the Philippines.

1

ADDITION OF SIMILAR FRACTIONS

Objectives: Visualize addition of similar fractions. Add similar fractions.

A. Identify the similar fractions from each set of fractions below. Write it on your paper.

1) 32 ,

23 ,

31 ,

52 _________________

2) 65 ,

32 ,

61 ,

85 _________________

3) 43 ,

83 ,

32 ,

42 _________________

4) 98 ,

81 ,

92 ,

41 _________________

5) 63 ,

98 ,

62 ,

43 _________________

Check your answer using the answer key. If you have a perfect score, you

may now proceed to this lesson. If not, review your past lessons.

Review

2

Read the problem.

Look at the region below. We say: 4 eighths plus 3 eighths equals 7 eighths

We write 84 +

83 =

87

Sum of numerators Same denominator

Let’s solve the problems following the steps in problem solving.

1. What is asked for? The part of the cake that was eaten.

2. What are the given data?

• 84 part of the cake eaten by the children

• 83 part of the cake served to the guests

Mother baked a cake. The children ate 84 of the cake. Some guests

came and were served 83 of it. What part of the cake was eaten.

Study and Learn

3

3. What is the mathematical sentence?

84 +

83 = n

4. So, 84 +

83 =

87

Let’s have another example. Study this diagram and state the addition of two fractions.

+ =

41

42

43

- When you add the two fractions, do you add the numerator? Yes

Do you add the denominators? No Why? Because the denominators are the same

- What kind of fractions are they? Similar fractions Find the sum of these illustrations.

61

62

What is the sum? 63

Is 63 in lowest terms? no

4

How can you express it in lowest terms? Divide the numerator and denominator by the same number, which is 3. 3 ÷ 3 1

= 6 ÷ 3 2

A. Find the value of n. Copy and answer the mathematical sentences in your notebook. Express the answers in lowest terms if needed. Use the figure to help you.

1) 2) 3)

21 +

21 = n

41 +

42 = n

64 +

61 = n

4) 5)

51 +

54 = n

82 +

84 = n

B. Add and express each sum to lowest terms, if possible

Do them in your paper. 1)

122 +

25 = 2)

103 +

104 =

Try These

5

3) 61 +

62 = 4)

83 +

87 =

5)

62 +

65 = 6)

102 +

109 =

7) 85 +

86 = 8)

93 +

99 =

9) 62 +

63 = 10)

187 +

185 =

C. Read the problem carefully. Then solve them on your paper.

1) Cresie has 81 metre of red ribbon and

84 metre of blue ribbon. How much

ribbon does Cresie have?

2) Henry gives Cresie another 86 metre of red ribbon. How many metres of

red ribbon does Cresie have now?

3) Wincel mixed 42 litre of white paint and

43 litre of blue paint. What part of

a litre is the mixture?

4) Katrina and Aga spent 21 hour practicing their first song and

21 hour

practicing their second song. How much time was spent practicing both songs?

How do we add similar fractions?

To add similar fractions, add the numerator and write the sum over the common denominator. Express the sum in lowest terms, if possible

Wrap Up

6

A. Find the sum. Express it in lowest terms, if possible.

1) 91 +

93 +

94 = 2)

85 +

82 =

3)

122 +

125 = 4)

93 +

92 =

5)

154 +

152 +

155 = 6)

65 +

61 =

7) 204 +

203 = 8)

2010 +

203 =

9) 214 +

213 = 10)

126 +

125 =

Check your answer with the answer key. If you get…. 8-10 - Excellent! You may now proceed to the next lesson. 5-7 - You need to review the processes you missed. 0-4 - You need to repeat the whole process. Ask your teacher or elder to help you.

On Your Own