In Elementary Mathematics Grade 4

Lesson Guide

In

Elementary Mathematics

Grade 4

Reformatted for distribution via DepEd LEARNING RESOURCE MANAGEMENT and DEVELOPMENT SYSTEM PORTAL

DEPARTMENT OF EDUCATION BUREAU OF ELEMENTARY EDUCATION

in coordination with ATENEO DE MANILA UNIVERSITY

2010

Chapter I

Whole Numbers

Comprehension of Whole Numbers

INSTRUCTIONAL MATERIALS COUNCIL SECRETARIAT, 2011

Lesson Guides in Elementary Mathematics Grade 4 Copyright © 2003 All rights reserved. No part of these lesson guides shall be reproduced in any form without a written permission from the Bureau of Elementary Education, Department of Education.

The Mathematics Writing Committee

GRADE 4 Region 3

Evelyn H. Magpayo – Pampanga Myrna Vicente – Nueva Ecija Ester Ramones – Tarlac Virgie Costales - Zambales

Region 4 – A (CALABARZON)

Flordeliza D. Yamo – Laguna Araceli C. Montoya – San Pablo City Estelita Q. del Rosario – Cavite City

National Capital Region (NCR)

Remylinda T. Soriano – Manila Maria Brucal – Makati Lina Seña – Taguig/Pateros Analee Pacaña – Pasig/San Juan

Bureau of Elementary Education (BEE)

Rogelio O. Dones Leony M. Achacoso Zosima C. Ventura

Ateneo de Manila University

Eva Marie Guevarra

Support Staff

Ferdinand S. Bergado Ma. Cristina C. Capellan Emilene Judith S. Sison Julius Peter M. Samulde Roy L. Concepcion Marcelino C. Bataller Myrna D. Latoza Eric S. de Guia – Illustrator

Consultants

Fr. Bienvenido F. Nebres, SJ – President, Ateneo de Manila University Carmela C. Oracion – Ateneo de Manila University

Pacita E. Hosaka – Ateneo de Manila University

PROJECT MANAGEMENT

Yolanda S. Quijano – Director IV Angelita M. Esdicul – Director III

Simeona T. Ebol – Chief, Curriculum Development Division Irene C. de Robles – OIC, Asst. Chief, Curriculum Development Division

Virginia T. Fernandez – Project Coordinator

EXECUTIVE COMMITTEE

Jesli A. Lapus – Secretary, Department of Education

Jesus G. Galvan – OIC, Undersecretary for Finance and Administration Vilma L. Labrador – Undersecretary for Programs and Projects

Teresita G. Inciong – Assistant Secretary for Programs and Projects Printed By: ISBN – 971-92775-3-x

iii

TABLE OF CONTENTS

Introduction .................................................................................................................................. iv Matrix ........................................................................................................................................ v

I. Whole Numbers

A. Comprehension of Whole Numbers

Numbers from 100 001 through Millions/Billions ............................................................ 1 Place Value .................................................................................................................... 4 Reading and Writing Numbers through Millions/Billions in Words ................................. 7 Rounding Off Numbers to the Nearest Tens .................................................................. 9 Rounding Off Numbers through Hundred Thousands ................................................... 13 Rounding Off Numbers to the Nearest Millions and Billions .......................................... 15

iv

I N T R O D U C T I O N

The Lesson Guides in Elementary Mathematics were developed by the

Department of Education through the Bureau of Elementary Education in

coordination with the Ateneo de Manila University. These resource materials

have been purposely prepared to help improve the mathematics instruction in

the elementary grades. These provide integration of values and life skills using

different teaching strategies for an interactive teaching/learning process.

Multiple intelligences techniques like games, puzzles, songs, etc. are also

integrated in each lesson; hence, learning Mathematics becomes fun and

enjoyable. Furthermore, Higher Order Thinking Skills (HOTS) activities are

incorporated in the lessons.

The skills are consistent with the Basic Education Curriculum

(BEC)/Philippine Elementary Learning Competencies (PELC). These should be

used by the teachers as a guide in their day-to-day teaching plans.

v

MATRIX IN ELEMENTARY MATHEMATICS Grade IV

COMPETENCIES VALUES INTEGRATED STRATEGIES USED MULTIPLE INTELLIGENCES

TECHNIQUES

I. WHOLE NUMBERS

A. Comprehension of Whole Numbers

1. Read and write numbers through

millions in symbols and in words

1.1 Identify numbers from 100 001 through millions/billions

Carefulness

Group and check Concept development

Number writing, Manipulative, Hands-on activities

1.2 Give the place value of each digit in a 6- or more digit numbers

Active participation Cooperation

Concept development Looking for pattern Educated guess

Hands-on activities, Manipulative, Writing, Charting

1.3 Read and write numbers through millions/billions in symbols

Honesty Concept development Educated guess Cooperative learning

Reading, Writing, Speaking, Charting, Hands-on activities, Cooperative learning, Manipulative

1.4 Read and write numbers through millions/billions in words

Cooperation Concept development Reading, Writing, Hands-on activities, Manipulative

2. Round off numbers to the nearest 2.1 tens

Cooperation

Concept development Educated guess Looking for pattern

Completing tables, Drawing, Writing

hundreds thousands ten thousands hundred thousands

Cooperation Friendliness

Concept development Educated guess

Speaking, Completing tables, Reading, Charting

millions billions

Thriftiness Concept development Guess and check

Self-awareness, Hands-on activities, Cooperative learning, Graph, Reading

1

Numbers from 100 001 through Millions/Billions

I. Learning Objectives

Cognitive: Identify numbers from 100 001 through millions/billions Psychomotor: Write numbers from 100 001 through millions/billions Affective: Practice carefulness in writing numbers through millions/billions

II. Learning Content

Skills: 1. Identifying numbers from 100 001 through millions/billions 2. Writing numbers from 100 001 through millions/billions

References: BEC – PELC I.A.1.1 textbooks in Math 4 Materials: flash cards, chart, place value chart, set of numbers written on

cards with cord Value: Carefulness

III. Learning Experiences

A. Preparatory Activities 1. Drill

Ask for 10 volunteers. Give each a number tag. Have them wear the cord with numbers

from 0 to 9. Guide the pupils to form 3- to 6-digit numbers. Ask the pupils who are sitting to read the numbers orally.

Example: a)

b)

c) d) e)

2. Review Pick out the numbers less than 100 001 from the sets of numbers posted on the houses.

3. Motivation

Start by playing “Guess What Number”. The teacher places the following statements on the board: a. My telephone number is “III II II - II III IIII”. b. The space capsule is circling the earth every “> > > IIIIII”.

7 3 2 4 1

7 4 2

5 8 6 9 0

8 2 7 5 9

5 4 6 2 3 1

8 432 10 100

6 789 436 132

7 634 99 999

100 000 436 849

138 472 24 382

89 432 94 389

45 489 634 312 123 421

2

c. I traveled “CDLXXIV” kilometres by motorcycle.

Do you think the sentences are easy to read and understand? Why? Do you think the symbols III II II - II III IIII, > > > IIIIII, CDLXXIV can be represented in our

numeration system? Why? What numbers do you think these numerals represent?

B. Developmental Activities

1. Presentation

a. Read the data.

Traffic in Metro Manila is heavy because nearly one-half of the

2 904 487 vehicles in the country are registered here.

1) What is the given number? (2 904 487) 2) How do we read it? (2 million, 904 thousand, 487) 3) How do we write it in words? (Two million, nine hundred four thousand, four hundred

eighty-seven) 4) Is the number easy to read and understand? Why? (Yes, because it is written in

standard form.) b. Present the number in the place value chart.

MILLIONS THOUSANDS UNITS

hundreds tens ones hundreds tens ones hundreds tens Ones

2 9 0 4 4 8 7

2

millions 9 hundred thousands

0 ten

thousands

4 thousands

4 hundreds

8 tens

7 ones

1) Ask them to give the digit in the one millions place, in hundred thousands place, ten thousands place and so on.

2) Ask them to give the expanded form then give the value of each digit. 3) Repeat the activity on billion numbers.

Example: 15 086 912 403357 296 324 081 How many periods are there in millions? How many digits are found in billions?

c. Present the lesson using an abacus with 12 rods. An improvised abacus may be made

using bottle caps, pieces of wood or balls for the beads, a piece of wooden board for the stand and a thick wire or banana cue stick for the post. Let the pupils show the number 487 293 465 on the abacus. Then ask them what digit is represented by the beads on each rod? Present also numbers in billions place.

2. Guided Practice

Activity 1 Put a check () if the number is in millions and a cross (x) if it is in billions.

___a) 6 386 798 ___b) 76 998 289 584 ___c) 17 633 549

3

Activity 2 Write M if the number is in millions and B if it is in billions.

___a) 89 679 289 548 ___b) 3 386 798 ___c) 456 126 834

Activity 3 Write a number on your paper that has 11 digits.

1) 7 in the ten billions place. 2) A digit that is 5 less than 8 in the one thousands place. 3) 4 in the hundred millions place.

3. Generalization How do you identify a number in million or in billion?

Million has three periods. It contains 7, 8 or 9 digits. Billion has four periods. It contains 10, 11 or 12 digits.

C. Application

Read the data. Write the number words in figures. 1. One drop of blood contains about five million red blood cells. 2. The human eye can see more than seven million, five hundred thousand color

differences. 3. During an average lifetime, the human heart beats about two billion, five hundred million times.

IV. Evaluation

A. Write T if the number is in thousands, M if it is in millions and B if it is in billions

___1) 6 034 597

___2) 145 793 000

___3) 206 000 371 148

___4) 52 758 137

___5) 425 010

B. Arrange each of the following sets of numbers starting from the thousands, millions and billions

place. Rewrite them on your paper. 1) 4 759 248 804; 541 298; 532 689 012

2) 205 946 101; 423 543 103 811; 988 415

3) 726 054; 7 685 004 208; 8 684 452

4) 29 673 000; 127 683; 1 542 678 725

5) 75 942 376 055; 24 673 503; 898 145

C. Examine the given numbers below. Write them in the proper place where they should belong. Be

sure that the numbers in each column are written from the smallest to the greatest.

15 086 912 305 674 981 643 212 002

17 196 741 014 357 296 324 899 120 741 019

185 451 9 273 050 357 296 234 8 095 403 002

4

BILLIONS MILLIONS THOUSANDS

V. Assignment

Study the given numbers. Copy the number which does not belong to the group.

1) 718 345 210 340; 151 968 254; 219 742 036

2) 50 307 501; 500 897 621 543; 15 718 260 345

3) 258 154; 508 476; 8 696 425

4) 3 274 503; 310 608; 2 830 458

5) 450 187 402; 897 500 126; 2 247 364 869

Place Value


Cognitive: Give the place value/value of each digit in a 6- or more digit number Psychomotor: Read and write numerals up to the hundred billions place Affective: Participate actively


Skills: 1. Identifying the place value and value of each digit in a 6- or more digit number 2. Reading and writing numerals up to the hundred billions

References: BEC – PELC I.A.1.2 textbooks in Math 4

Materials: place value chart, number cards, number words, flash cards Values: Active participation and being considerate


A. Preparatory Activities

1. Drill Have a drill in the form of a game. “Number Tag Game” a. Each group will have a set of numbers from 0 to 9. b. Pupils will form the number given by the teacher.

The number must be less than 6 digits. Example: 79 384 c. First group to form the digit will be the winner.

2. Review

Reading and writing numerals in the standard form using different ways.

5

“Matching Game” Mechanics: Divide the class into 2 groups. A representative from each group takes turn in answering or matching the numeral with its number name or word name.

A B

37 1 thousand 3 hundreds 5 tens 6 ones

145 Thirty-seven

1 356 Eight hundred twenty-six thousand, one hundred forty-one

24 295 1 hundred 4 tens 5 ones

826 141 20 000 + 4 000 + 200 + 90 + 5

3. Motivation

Ask the pupils why smaller pupils are seated in front while the bigger pupils are seated at

the back. Help the pupils realize that people must be considerate to get along well with others.


1. Presentation

a. Tell the pupils that numbers are like people. They can be grouped in many ways. b. Discuss the three ways in representing numbers in standard form.

3 765 1) word form: three thousand, seven hundred sixty-five 2) number and abbreviation form: 3th 7h 6t 5 ones 3) number and word: 3 thousands 7 hundreds 6 tens 5 ones

c. Show a place value chart which is up to the hundred billions place. Tell the pupils that our system of numeration has digits grouped in threes, we call them PERIODS.

Billions Millions Thousands Units

Hundreds Tens Ones Hundreds Tens Ones Hundreds Tens Ones Hundreds Tens Ones

2 0 6 4 3 7 6 1 2 9 7 5

2. Group Activity

a. Groups will be given activity sheets with the data below written on them. b. Tell them to follow the directions in writing the data.

Directions: Give the place value and the value of the underlined digits 2 3 7 9 8 7 4 3 2 1 4 2

Digit Place Value Value

c. Show more exercises in identifying the place value and value of each digit in a 6- or more

digit numeral using number cards. (This will be done orally.) Give the place value and the value of the digit 6 in each numeral:

6

a) 864 439 b) 826 453 c) 682 975

d) 86 451 197 e) 126 458 360 f) 26 974 431 100

d. Have a game on the different skills learned for the day.

Do blackboard relay. Divide the class in columns. Each pupil takes turn in writing the correct answer on

the board. The column with the most number of correct points wins. Questions: 1) What is the value of 6 in 64 395? 2) What is the value of 4 in 1 462 587? 3) In the numeral 45 376 192, what digit is in the one millions place? 4) What is the standard form of sixty-five billion, one hundred four million, two hundred

thirty-seven thousand, eighty-six? 5) What is the standard form for 9m 6hth 3tth 8h 7ones?

3. Generalization

How do you tell the value of each digit in a given number? Valuing: ● Did you participate in the activities today?

Rate yourself: 5-highest and 1-lowest

C. Application Write each digit of the given number in the place value chart. 1) 144 785 2) 27 436 192 3) 3 007 518 692

Billions Millions Thousands Units

H T O H T O H T O H T O

1)

2)

3)

IV. Evaluation

A. Give the value of each digit in the number 27 436 198.

1) 2 _____ 5) 6 _____ 2) 7 _____ 6) 1 _____ 3) 4 _____ 7) 9 _____ 4) 3 _____ 8) 8 _____

B. Answer the following:

1.

a. Form the smallest number using all the digits above. b. Form the smallest odd/even number using all the digits above. c. Form the largest odd/even number using all the digits above.

2. Show, using drawing, that 235 has 23 tens. Explain further in words.

2 6 4 7 5 1

7

3. Who am I? My tens digit is 2 times my hundreds digit. My hundreds digit is 4. My ones digit is a factor of my tens and hundreds digit.

4. Use the digits 1, 2, 3, 4, 5, 6, 7, 8 only once: a. Write the greatest number possible with 5 in the hundred thousands place b. Write the least number possible with 8 in the one millions place.

V. Assignment

Write ten numbers up to millions/billions in the standard form.

Reading and Writing Numbers through Millions/Billions in Words


Cognitive: Read and write numbers through millions/billions in words Psychomotor: Write numbers in words correctly Affective: Participate actively in different activities


Skill: Reading and writing numbers through millions/billions in words References: BEC–PELC I.A.1.4

textbooks in Math 4 Materials: flash cards, charts Value: Cooperation



Reading of numbers.

242 186 246 386 187 623 305 160 65 187

2. Review Teacher will dictate these numbers and pupils will write them in their show-me-cards.

682 468 23 694 3 743 7 218 946 569

3. Motivation How many digits has 723 964 157 368? Can you write the number in words?

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1. Presentation

The land surface of the earth is 148 892 864 square kilometres and the water surface is 362 011 332 square kilometres.

a. Discuss

1) How many square kilometres is the land surface? Write it on the board. 2) How many square kilometres has the water surface? Write it on the board. 3) How many digits has the land surface area? How about the water surface area? 4) Read the numbers. 5) Write the numbers in words.

b. Read and write the word name for each numeral. 1) 389 152 247 2) 2 714 683 389 3) 1 186 792 053 4) 9 544 416 936 5) 7 110 313 425

2. Group Activities

Let’s have a contest. “Groups 1 and 2 form your line. 5 members each group.” (Infuse the value of active participation.) Get a number card in the box and match it with the word names in the pocket chart. Those who finish first should be commended. a) 85 312 914 677 b) 18 000 777 283 c) 109 067 214 511 d) 87 782 570 308 e) 5 112 914 000

3. Fixing Skills/Practice

Read and answer the following: a. The Bureau of Forest Development donated three seedlings each for school children all

over the country. The total number of seedlings was 15 223 564 821. Write this figure in words.

b. Mrs. Luna’s shell craft factory used five hundred eighty-six million, three hundred twenty-four thousand, three hundred eighty-two shells in one year. Write the number of shells in symbols.

c. Zero has no value. Can we just leave the space for zero vacant? Why? d. Is zero important in writing numbers? e. How would you write 204 000 785 083 in words? Valuing:

Did you participate in the activity? How? What did you share with your group? Do you also practice this at home? How?

9

4. Generalization

How are numbers written in words?

The numbers are written in words in the same way that they are read.

IV. Evaluation

A. Match the figures with the correct words

1) 3 411 789 a) Sixteen million, three hundred eighty-three thousand, one hundred five

2) 16 383 105 b) Four billion, five hundred sixty-eight thousand, one hundred

seventy-two 3) 205 168 347 c) Three million, four hundred eleven thousand, seven hundred

eighty-nine 4) 3 521 681 d) Three million, five hundred twenty-one thousand, six hundred

eighty-one 5) 4 000 568 172 e) Two hundred five million, one hundred sixty-eight thousand,

three hundred forty-seven

B. Write the figure in words. 1. Increase by 5 the digit in the billions place of the numeral 6 478 921 720 to form a new

number 2. Write in words the standard form of this numeral

6 000 000 + 400 000 + 70 000 + 8 000 + 500 + 20 + 3

C. Write in figures. 1. One billion, five million, five hundred twenty thousand, twenty-eight 2. Nine billion, six hundred two million, five hundred forty-one thousand, two hundred ninety-

eight V. Assignment

Write the number in words. a. 6 463 342 264 b. 520 175 786 c. 23 596 384 103 d. 501 000 176 330 e. 43 781 648 134

Rounding Numbers to the Nearest Tens


Cognitive: 1. Round numbers to the nearest tens

2. Identify the place value of the digit in a given numeral Psychomotor: 1. Use a number line to show rounded off numbers

10

2. Give the place value/value of the digit in a given numeral Affective: Cooperate during group activities


Skills: 1. Rounding numbers to the nearest tens 2. Identifying place value/value of a digit in a numeral

References: BEC–PELC I.A.2.1 textbooks in Math 4 Materials: charts, activity cards, number lines Value: Cooperation



“Guessing Game”

Divide the class into 2 groups. All pupils will solve the given problem as fast as they can. The first pupil who gives the correct answer wins. a. My ones digit is 2. My tens digit is thrice the ones digit. My hundreds digit is four times

the ones digit and my thousands digit is the sum of the ones and the tens digit. What number am I?

b. I am an 8-digit number. My thousands digit is 9. My ten millions digit is 3. My hundreds digit is 6. The other digits are 0. What number am I?

2. Review

Write the place value and the value of the underlined digit in each of the following numbers.

35 492 73 985 1 591 635 469 789 143 785 19 432 156 000

3. Motivation

Ask a pupil to read a news item that shows estimation. Examples: Last week, a company manager called for a meeting. Almost 50 employees

came.

Did the actual number of employees attend the meeting?

What word was used which expressed an estimate? (almost) The population in our school is about 2 000 pupils. What word in the sentence expresses an estimate? (about)


1. Presentation

a. Read the problem carefully, then answer the questions briefly.

Rica, a Grade 4 pupil needs 27 for her school project. She did not ask

money from her parents because she has saved 30 from her daily allowance. What kind of a girl is Rica?

1) Who is Rica? What does Rica need? 2) How much money does she need for the school project? 3) Where did she get the money?

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4) How much is her savings? 5) What kind of a girl is Rica?

b. Present a number line showing numbers from 20 to 30.

Draw a ring around 27. Ask: Is 27 closer to 20 or to 30?

20 21 22 23 24 25 26 27 28 29 30

2. Analysis/Abstraction

Looking back at the number line, is 27 nearer to 20 or to 30? Number 27 is nearer to 30 than 20. So, if we round 27 to the nearest tens, it will become 30.

Valuing:

How did you find the activity?

What kind of a girl is Rica?

Are you like Rica? Do you also save a certain amount from your daily allowance?

3. Fixing Skills

Let the pupils group themselves into 4 and perform the activities in the activity sheet. Emphasize the value of cooperation. Let them relate how they cooperate with other members of their group. Group 1

Original Number Rounded to the nearest tens

15

43

79

32

64

Group 2


126

342

568

269

644

853

Group 3


1 349

4 784

8 632

3 786

7 755

12

Group 4


16 277

28 163

56 788

33 154

17 416

10 112

4. Generalization

How do we round numbers to the nearest tens?

In rounding numbers to the nearest tens, look at the digit at the right of the tens digit. If the number is 5 or more, add 1 to the tens place, if the digit is less than 5, retain the tens digit. Change the ones digit to zero.

C. Application

Round the following to the tens place. a. 342 b. 4 638 c. 5 419 d. 28 326 e. 49 749

IV. Evaluation

Study the number line below. Answer the following questions.

1.

20 21 22 23 24 25 26 27 28 29 30 31

a. Draw a ring around 26. Is 26 closer to 20 or to 30? When rounded to the nearest tens,

26 will become ____. b. Draw a square around 24. Is 24 closer to 20 or to 30? What will happen to 24 when

rounded to the nearest tens? c. Cross out (X) 28. Is 28 closer to 20 or to 30? When rounded to the nearest tens, 28 will

become ____. d. Check () 21. Is 21 closer to 20 or to 30? How will 21 be rounded to the nearest tens?

2. Answer each question by rounding the given number to the nearest tens.

a. Lydia has 37 rubber bands. Around how many rubber bands does Lydia have? b. Mother bought 43 bananas. Around how many bananas did mother buy? c. When 83 is rounded to the nearest tens, 83 will become___. d. Mang Tony gathered 94 eggs in the poultry farm. About how many eggs did Mang Tony

gather? e. If rounded to the nearest tens, 769 becomes ___.

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V. Assignment

Round the following numbers to the nearest tens. a. 362 b. 837 c. 5 742 d. 6 424 e. 9 654

Rounding Numbers through Hundred Thousands


Cognitive: Round numbers to the nearest hundreds, thousands, ten thousands and hundred thousands

Psychomotor: State the rules in rounding numbers correctly Affective: Find joy in working with others and doing something for others


Skill: Rounding numbers to the nearest hundreds, thousands, ten thousands and hundred thousands

References: BEC–PELC I.A.2.4-2.5 textbooks in Math 4

Materials: chart, number cards Values: Cooperation and friendliness



1. Drill

Teacher picks out numbers one at a time from a box. The task of each pupil is to round these numbers to the nearest tens.

Example: 37 rounds to 40 21 rounds to 20

2. Review

How do we round numbers to the nearest tens? Show examples on the board. Elicit from

the pupils the rule in rounding numbers to the nearest tens.

3. Motivation

Which of the following numbers can be rounded to 400? 600? 385 349 562 515 571

37

21

14


1. Presentation

There are 371 582 residents in the city of Makati and 256 454 residents in

Pasay City who are benefiting from the Clean and Green Program of the government.

Look at the table below and examine how the numbers 371 582 and 256 454 have been rounded.

Number Nearest

Hundreds Nearest

Thousands Nearest Ten thousands

Nearest Hundred Thousands

371 582 371 600 372 000 370 000 400 000

256 454 256 500 256 000 260 000 300 000

2. Analysis/Abstraction

Discuss the given problem. a. What cities benefited from the Clean and Green Program of the government? b. How many residents benefited in the city of Makati? Pasay City? c. Round 371 582 to the nearest hundreds, thousands, hundred thousands. d. Round 256 454 to the nearest thousands, ten thousands, hundred thousands.

Let us try rounding numbers to the nearest: hundreds, thousands, ten thousands, hundred thousands. (Group the pupils into 5 groups or more depending on the size of the class.) Stress the value of cooperative learning and friendliness. 1. Round the numbers to the nearest hundreds and to the nearest thousands. 2. Round the numbers to the nearest ten thousands and to the nearest hundred

thousands. a) 831 732 b) 925 501 c) 655 321 100 d) 531 841 215 e) 736 386 133

3. Group Activities

Let each group report to class the answer in the activity sheet assigned to them.

Encourage pupils to state the rule in their own words. Example: Pupil 1: Round 456 837 to the nearest ten thousands.

Pupil 2:The answer is 460 000. Round 329 465 to the nearest hundred thousands.

Pupil 3: 300 000, etc.

4. Generalization

How do we round numbers to the nearest hundreds, thousands, ten thousands and hundred thousands?

Round up if the digit to the right of the digit to be rounded is 5, 6, 7, 8 and 9. Round down if the digit to the right of the digit to be rounded is 0, 1, 2, 3 and 4.

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C. Application 1. Round the following numbers to the nearest ten thousands then answer the questions that

follow. a. 25 743 = _____ Did you round up or down? b. 15 652 = _____ Is your answer 20 000? How did you get the answer? c. 34 730 = _____ How will you round to the nearest thousands? d. 76 348 = _____ Did you round up? Why? e. 89 192 = _____ Is the answer 80 000? Why? State the rule.

2. Read the following situations below. Tell whether the number has an exact value or an

estimated value. a. Mrs. Reyes lives at 10 Monte de Piedad Street. b. There were 1 275 people at the auditorium. c. Karen’s student number is 15 031. d. In school there were about 150 seats at the cafeteria.

IV. Evaluation

Round each of the following to its nearest specific place value.

Numbers Ten Thousands Hundred Thousands

1) 127 563

2) 486 170

3) 816 342

4) 374 139

5) 732 256

V. Assignment

Round the number to the place value of the underlined digit. a. 238 789 d. 793 948 b. 394 634 e. 943 431 c. 545 381

Rounding Numbers to the Nearest Millions and Billions


Cognitive: Round numbers to the nearest millions and billions Psychomotor: Tell numbers rounded off to the nearest millions and billions Affective: Appreciate the importance of being thrifty


Skills: 1. Rounding numbers to the nearest millions and billions 2. Identifying numbers rounded off to the nearest millions and billions

References: BEC–PELC I.A.2.6-2.7 textbooks in Math 4

Materials: flash cards, activity cards Value: Thriftiness

16



1. Drill

Reading numbers through millions/billions 2. Review

How do we round numbers to the nearest hundred thousands? Recall the steps in rounding numbers to its nearest specific place value.

3. Motivation

Have you been to a cement factory? What did you see there? Do you have an idea about

the number of bags of cement that can be manufactured in a month?


1. Presentation Read and understand the story on the activity card carefully.

Mary’s Cement is a big factory. It supplies cements to the whole country. Last year, Mary’s Cement delivered a total of 64 768 117 bags to Visayas and Mindanao. About how many bags of cement were delivered in all?

a. What product does Mary’s Cement Factory have? b. Is cement manufacturing a good business? Why? c. Why do most people buy cement? d. What was the actual number of cement delivered to Visayas and Mindanao? e. What will the number be if rounded off to the nearest ten millions? f. How did you get 60 000 000? g. Which of these rules do you use?

Round up if the digit to the right of the digit in the millions place is 5, 6, 7, 8 or 9. Round down if the digit to the right of the millions place is 0, 1, 2, 3, or 4.

Show and discuss another problem in class.

One of the wealthiest men in Asia opened a savings account in a Philippine bank with an

initial deposit of 25,643,914,377.00. About how much is his deposit in the bank? a. Who opened a savings account in a bank? b. Why do you think he keeps his money in the bank? c. About how many billions was his initial deposit? Valuing: ● If you have plenty of money, what will you do? Will you save some of it? If you have little

money, will you still save? Why? ● How would your savings affect your life in the future? Let the pupils show their work on activities 1 & 2 on the board.

17

Activity 1

Number 64 768 117

Nearest Millions 65 000 000

Activity 2

Number

25,643,914,377.00

Nearest Billions

26,000,000,000.00

2. Guided Practice

Let us play a game. Form 2 groups of pupils, the yellow group and the red group. The

group who can round the numbers first to the nearest millions wins. Are you ready now? The

numbers are inside the boxes in front of your group. a) 8 856 000 b) 23 431 785 c) 4 180 374 d) 42 683 360 e) 9 793 205 f) 75 413 000 g) 6 316 348 h) 17 938 172 i) 2 630 539 j) 136 715 340

Do the same in billions. Call on the pupils who did not participate in the first game then

give them the same directions stated in the first activity. The numbers are inside the box. Play blackboard relay. a) 2 942 628 241 b) 23 592 176 302 c) 5 341 707 333 d) 47 234 346 532 e) 14 603 100 784 f) 92 739 316 035 g) 6 421 125 000 h) 16 484 148 703 i) 17 725 823 421 j) 345 800 000 145

Winners should be commended.

3. Generalization

How do we round numbers to the nearest millions/billions? Round up if the digit to the right of the millions/billions place is 5, 6, 7, 8, and 9. Round down if the digit to the right of the place to be rounded is 0, 1, 2, 3 and 4.

C. Application

Round off to the nearest millions/billions.

Number Nearest Millions Nearest Billions

6 831 462 126 a. f.

2 124 549 314 b. g.

8 314 183 512 c. h.

27 573 976 249 d. i.

15 439 873 831 e. j.

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IV. Evaluation

A. Choose the letter of the correct answer.

1. During the Christmas season, a hotdog company delivered 3 745 000 bags of hotdogs to 3 986 rolling stores all over Metro Manila. Round 3 745 000 to the nearest millions. a. 4 000 b. 3 000 000 c. 4 000 250 d. 4 000 000

2. A certain tire supplier distributes different sizes of tires all over the country. The number of

tires is supplied 236 435 677. How will you round this number to the nearest hundred millions? a. 236 000 000 b. 200 000 000 c. 240 000 000 d. 300 000 000

B. Name the place value in which the following numbers are rounded.

1) 287 455 rounded to 290 000 ____________ 2) 27 643 189 rounded to 28 000 000 ___________ 3) 458 096 245 rounded to 500 000 000 ____________ 4) 35 613 827 549 rounded to 35 610 000 000 __________ 5) 57 924 603 285 rounded to 58 000 000 000 __________

V. Assignment

The table gives the distance of the five planets from the sun. Round the figures to the nearest hundred millions and nearest billions.

Planet Distance from the sun in kilometers

Nearest Hundred Millions

Nearest Billions

1. Jupiter 778 300 000

2. Saturn 1 427 000 000

3. Uranus 2 869 600 000

4. Neptune 4 496 700 000

5. Earth 150 000 000

Documents

In Elementary Mathematics Grade 4