MODUL VII Perkalian Pecahan Untuk Kelas 1 SMP / MTs

MODUL VII

Perkalian Pecahan

Untuk Kelas 1 SMP / MTs

By : Marsigit

Reviewed by : Eka Sulistyawati

A.    Fractions Multiplication

Issue 1:

Please you do the following activities if you are sharing tarts with a friend.

1.      Use a circular piece of paper to declare a cake. Fold and cut the paper into two parts which it’s same.

2.      How much the part of tarts are expressed by each piece paper, then write the value on piece of paper? Take one piece tart for you.

3.      Next cut the cake that you have into two same parts. Then give a part to your friend. How part your friend tarts that you have?

4.      What proportion of your friend tarts from first condition?

Issue 2:

Mother has 3 kg of wheat flour. Half of the flour will be given to the aunt while one third of the rest will be make a cake. How weight wheat flour to be made cakes by mother?
To answer this question, do the following steps:

Weight of wheat flour cake that will be made by the mother is the third from a
half of the flour entirely. Third statement of the half being written 1/3  x ½. So the weight of wheat flour to be made cakes by Mother is 1/3  x ½ = ...............

Issue 3:

Write a math sentence than a quarter of the fifth and count. To answer this question do steps:Quarter of the fifth statement can be written ¼  x 1/5 the results of multiplication is ¼ x 1/5 = .......

Issue 4:

Write math sentence of two-fifths of the six seventh and count . To answer this question, do these steps:

Statement two-fifths of the six-seventh can be written 2/5  x 6/7. The results of multiplication is 2/5  x 6/7 = ..........

Issue 5:

How do you perform multiplication integer with fractions or multiplication fractions with integer. So is there a difference between 4 x 1/3 and 1/3 x 4?

Consider the form multiplication of 4 x 1/3 . This form can be written as a for summation of 1/3 , it is 1/3  + 1/3 + 1/3 + 1/3 . So 4 x 1/3 = 1/3 + 1/3 +1/3 + 1/3 = 4/3. Now consider the form 1/3 x 4? To answer that question, consider the following issues and answer the question. The multiplication model can be obtained for example Ali has 12 markers. It is known that one-third of the number markers has been damaged. How many markers Ali has that have been damaged? Do you find that the number of  was damaged markers are 1/3 x 12 = 4 pieces

Issues 6: Determine the multiplication result of mix fractional 2 1/3 x 3 1/3. To answer this question, pay attention to the following picture:

                                    3 1/3   

            2 ½

The picture above shows the principle that the multiplication of two numbers can The area indicated by. Width of rectangle is 2 ½  a unit area The length of rectangle is 3 1/3 A unit area. So multiplication 2 ½  x 3 1/3 is a wide rectangle. From the picture above can be seen that the area of ​​rectangle is (2 x 3) + (3 x ½ ) + (2 x 1/3) + (1/2 x 1/3) = 6 + 1 1/2 + 2/3 + 1/6 = .....  a unit area. So,  2 ½  x 3 1/3 = ...........