MAT PG L6 M04C Solving Word Problems About Multiplication

Document Sample
MAT PG L6 M04C Solving Word Problems About Multiplication Powered By Docstoc
					            Are You Ready?

Let’s find out.

MULTIPLY.

     1.     .07              6.         .75
          × .07                       × .62
          ———                         ———


     2.     3.45             7.         68.53
          ×    3                      ×   10
          ———                         ————


     3.     71.22            8.         43.57
          ×    16                     × 100
          ————                        ————


     4.    5.64              9.         8.93
          × 16                        × 10
          ———                         ———


     5.     .23              10.        86.34
          × 14                        ×    71
          ———                         ————




                                  1
 FEEDBACK

 1.   .0049

 2.   10.35

 3.   1139.52

 4.   90.24

 5.   3.22

 6.   .4650

 7.   685.30

 8.   4357.00

 9.   89.30

10.   6130.14




                2
 LESSON
             Solving Word Problems About
  1          Multiplication of Decimals

    In this lesson, you will learn to solve word problems about multiplication of
decimals including money.

    Here’s a problem. Read it carefully.

    A soap factory gave out wrist watches to 1000 persons. Each wrist watch costs
P 1524.00. How much did the factory spend for all the wrist watches?

    Here’s how to solve the problem step by step.

    Step 1. Write down the given facts.

    Given:   1000 persons
             P 1,524.00 cost of one wrist watch.

    Step 2. Write down what is asked in the problem.

    Question Asked:
             How much did the factory spend for all the wrist watches?

    Step 3. Write down the operation to be used.

    Operation: Multiplication.

    Step 4. Write down the number sentence.

             Number sentence:      1000 × 1524.00 = N




                                           3
    Step 5. Solve the problem.

    Solution:

         P 1,524.00        –      cost 1 wrist watch
         × 1000                   number of persons given a wrist watch
       1,524,000.00    –       Total amount spent by the factory for the wrist watches.


HERE IS A PROBLEM FOR YOU TO SOLVE. FOLLOW THE STEPS.

   Mrs. Torres, a store owner, bought 100 sacks of rice at P 550.00 each. How
much did she pay for all the sacks of rice?

    Step 1. Write down the given facts.

    Given:

    Step 2. Write down what is asked in the problem.

    Question Asked:

    Step 3. Write down the operation to be used.

    Operation:

    Step 4. Write down the number sentence.

    Number sentence:

    Step 5. Solve the problem.

    Solution:




AFTER WRITING YOUR ANSWERS, RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.

                                           4
Here’s another problem. Read it carefully.

Romulo earns P 90.00 a day. How much does he earn in 30 days?

Step 1. Given facts:

         P 90.00 amount earned in a day for 30 days

Step 2. Question asked:

         How much does he earn in 30 days?

Step 3. Operation to be used:

         Multiplication.

Step 4. Number sentence:

         30 × P 90.00 = N

Step 5. Solution:

         P 90.00           amount earned in a day
         ×      30         number of days
         ————
         P 2,700.00        amount earned in 30 days.




                                       5
HERE’S A PROBLEM FOR YOU TO SOLVE. FOLLOW THE STEPS. USE YOUR
ANSWER SHEET.

    A man drove 42.5 km per hour. How many kilometers did he drive in 8 hours?

    Step 1. Given facts:

    Step 2. Question asked:

    Step 3. Operation to be used:

    Step 4. Number sentence:

    Step 5. Solution:




AFTER WRITING YOUR ANSWERS, RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.

    Now, here’s how to solve a word problem without showing each step.

   Mrs. Gomez, a dressmaker, bought 60.25 meters of tetoron at P 40.00 per meter.
How much did she pay for the cloth?

    Solution:

         P 40.00
         × 60.25
         ————
             20000
             8000
             0000
             24000
         ————
         2,410.0000 – amount paid for the cloth.

                                        6
NOW, SOLVE THIS PROBLEM WITHOUT SHOWING THE STEPS ONE BY
ONE.

     For a school project, each pupil contributed P 25.75. How much was the total
collection if there are 2000 pupils?

    Solution:




AFTER WRITING YOUR ANSWERS, RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.



           Self-Test (Lesson 1)

READ EACH PROBLEM CAREFULLY AND SOLVE IT.

    1.   A softdrink company gave out television sets to 50 persons who won in a
         grand raffle. Each television set costs P 2395.75. How much did the company
         spend for all the television sets?

    2.   Ria bought 36.15 meters of ribbons at P 6.75 per meter. How much did she
         pay for all the ribbons?

    3.   Mr. Rodriguez earns P 7,180.85 a month. How much does he earn in 6
         months?

    4.   A sheet of thin paper is 0.004 inch thick. How thick would 85 sheets of
         paper be?

    5.   A man drove 62.25 km per hour. How many kilometers did he drive in 6
         hours?

AFTER WRITING YOUR ANSWERS, RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.

                                         7
           Summary

    In this module, you have learned to solve word problems about multiplication of
decimals including money.

    Here are the steps to follow in solving a word problem.

         Step 1. Write the given facts.

         Step 2. Write down what is asked in the problem.

         Step 3. Write down the operation to be used.

         Step 4. Write down the number sentence.

         Step 5. Solve the problem.




WHEN YOU ARE READY, GO TO THE TESTING ROOM AND TAKE THE
POSTTEST.
                                          8