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Lesson 4: Multiplying of Fractions

Multiply the fraction in the box to the fractions and whole numbers around it.

How do we multiply fractions with a whole number or another fraction?

Reflect: How do we multiply fractions with a whole number or another fraction?

The farmers in Barangay Pinagsama planted tomato on half of its 1 2/3 hectares of land. What part of the land was planted with tomato?

How will you answer this kind of problem?Reflect: What do you want to know about multiplication of fraction and mixed number?

The product of 12

and 123

can be

represented by the fraction bars on the right.

The mixed number 123

is equal to 53

in

improper fraction.

Multiplying 53

by 12

gives the partial

products of 36

and 26

. The sum of the partial

products is equal to 56

.

Here is a shorter way to multiply fraction and mixed number.1. Change the mixed number to

improper fraction.

19

512

34

123×

12

53×

12

123

=33+ 2

3=5

3

+ ¿ 56

26

36

12

of

Elaborate

Explain

2. Multiply the numerator and the denominator of the multiplicand to the numerator and denominator of the multiplier respectively.

53×

12=5×1

3×2=5

6

3. Reduce the product to its lowest form if necessary.

56

is already in lowest form.

With your seatmate, discuss another way of multiplying fractions and mixed numbers. Here are the ideas you should have learned in this lesson.

1. In multiplication of fraction and mixed number, follow these steps. a. Change the mixed number to improper fraction.b. Multiply the numerator and the denominator of the multiplicand to the numerator

and denominator of the multiplier respectively.c. Reduce the product to its lowest form if necessary.

A. Translate the following questions into multiplication phrases. Then compute for the products.

1. What is 14of 3

12

km?

2. What is 23of 2

58

dozen of eggs?

3. What is 38of 5

59

cups of flour?

4. What is 16of 6

910

liters of water?

5. What is 512of 10

27

hours?

B. After computing for the products of the fractions above, use your calculator to check if your answer is correct or not.

Example:

212×

14=5

8 on the calculator is

2 ab/c 1 ab/c 2 X 1 ab/c 4 =

20

Evaluate

Extend

A. Find the product of the following fractions and mixed numbers. Express your answer in lowest form.

1. 128

×23

2. 445

×56

3. 279

×125

4. 113

×214

×59

B. Make a model or representation of the following multiplication phrase.

5. 35×

49

6. 135

×34

7. 223

×118

C. Identify which of the following statement below is false based on the solution inside the box. Then explain your answer for each statement.

8. The mixed number 245

should be 125

in improper fraction.

9. The product of the fraction should be 1220

.

10. The lowest form of 1420

should be7

10.

D.Create a multiplication sentence that is equal to56 . The

multiplication sentence should have a fraction and a mixed number. Then make a step by step computation for the product.

Pause & Reflect

Are you happy with the result of your evaluation? Why?What concepts are clear to you?What concepts are still not clear to you?What is the most desirable value or attitude that you have developed in this lesson?

A. Answer the questions below. Is learning how to multiply fractions important? Why? Give at least 3 examples of situations where we use multiplication of fractions and mixed numbers.

B. Use a computer application to draw the models for following multiplication phrases. Then compute for their products. (Note: If you don’t have access to a computer, just draw the illustration using your pen and ruler on your notebook.)

21

14×2

45=N

14×

145

=N

14×

1420

=N

1×144×5

=N

1420

=34

a. 123×

14

b. 212×

35

22