Color profile: Disabled Composite Default screen MATHEMATICS for year 6 second edition Stan Pulgies Robert Haese Sandra Haese cyan Y:\...\SA_06-2\SA06_00\001SA600.CDR Thu Sep 18 16:38:53 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 Haese & Harris Publications black SA_06 Color profile: Disabled Composite Default screen MATHEMATICS FOR YEAR 6 SECOND EDITION Stan Pulgies Robert Haese Sandra Haese M.Ed., B.Ed., Grad.Dip.T. B.Sc. B.Sc. Haese & Harris Publications 3 Frank Collopy Court, Adelaide Airport SA 5950 Telephone: (08) 8355 9444, Fax: (08) 8355 9471 email: [email protected] web: www.haeseandharris.com.au National Library of Australia Card Number & ISBN 1 876543 62 0 © Haese & Harris Publications 2003 Published by Raksar Nominees Pty Ltd, 3 Frank Collopy Court, Adelaide Airport SA 5950 First Edition Second Edition 2000 2003 Cartoon artwork by John Martin and Chris Meadows. Artwork by Piotr Poturaj, Joanna Poturaj and David Purton Cover design by Piotr Poturaj. Cover photograph: Western Pygmy Possum © Nicholas Birks, Wildflight Australia Photography Computer software by David Purton and Eli Sieradzki Typeset in Australia by Susan Haese (Raksar Nominees). Typeset in Times Roman 10\Qw_ /11\Qw_ This book is copyright. Except as permitted by the Copyright Act (any fair dealing for the purposes of private study, research, criticism or review), no part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publisher. Enquiries to be made to Haese & Harris Publications. Copying for educational purposes: Where copies of part or the whole of the book are made under Part VB of the Copyright Act, the law requires that the educational institution or the body that administers it has given a remuneration notice to Copyright Agency Limited (CAL). For information, contact the Copyright Agency Limited. cyan Y:\...\SA_06-2\SA06_00\002SA600.CDR Wed Sep 24 15:49:26 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 Acknowledgement: the descriptors listed at the beginning of each chapter are taken from the R-7 SACSA Mathematics Teaching Resource published by the Department of Education and Children’s Services. black SA_06 Color profile: Disabled Composite Default screen FOREWORD Mathematics for Year 6 (second edition) offers a comprehensive and rigorous course of study at Year¡¡6 level. Through its worked examples, exercises, activities and answers, and the support of the interactive Student CD, the book provides students with the structure and content to work efficiently at their own rate. The book and CD package is designed to supplement classroom practice and give teachers time to explore other creative strategies, depending on the needs of their students. It is not the Year 6 Mathematics Curriculum, nor does it proclaim to provide the most effective teaching program. The knowledge, skills and understandings listed at the beginning of each chapter incorporate the descriptors used in the R-7 SACSA Mathematics Teaching Resource for Middle Years. We have listed the descriptors in the hope that this will be a helpful guide for Year 6 teachers who may wish to use the book to support their teaching practice. About this second edition: the second edition is a general revision and updating of the original text, with some reorganisation of chapters. Changes include: ! new sections on Speed and Temperature in the Time chapter ! a new section on Mass in the Solids chapter ! a new chapter Data Collection and Analysis, which combines Reading Graphs and Charts, and Data Analysis, and includes a new section Using Technology to Graph Data ! an extended chapter on Measurement, including perimeter, area, volume and capacity. ! the inclusion of an interactive Student CD In the table of contents, page numbers for corresponding sections in the first edition are given in brackets. This is intended as a guide for teachers who may wish to use the first and second editions within the same classroom. A glance at the contents pages will show how both books correlate (the absence of a page number in brackets denotes the introduction of a new section). About the interactive Student CD: the CD contains the text of the book. Students can leave the textbook at school and keep the CD at home, to save carrying a heavy textbook to and from school each day. But more than that, by clicking on the ‘active icons’ within the text, students can access a range of interactive features: graphing and geometry software, spreadsheets, video clips, computer demonstrations and simulations, and worksheets. The CD is ideal for independent study. Students can revisit concepts taught in class and explore new ideas for themselves. It is fantastic for teachers to use for demonstrations and simulations in the classroom. In summary, the book offers structure and rigour, and the CD makes maths come alive. We have endeavoured to provide as broad a base of activity and learning styles as we can, but we also caution that no single book should be the sole resource for any classroom teacher. We welcome your feedback. Email: [email protected] Web: www.haeseandharris.com.au cyan Y:\...\SA_06-2\SA06_00\003SA600.CDR Wed Sep 24 15:50:27 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 SP RCH SHH black SA_06 Color profile: Disabled Composite Default screen 4 TABLE OF CONTENTS TABLE OF CONTENTS 1 WHOLE NUMBERS 9 (9) 10 14 15 16 19 21 24 32 38 40 41 41 42 (10) POINTS, LINES AND CIRCLES 43 (41) A Points and lines B Polygons C Angles D Perpendicular lines E Triangles and quadrilaterals F Angles in triangles G Angles in quadrilaterals H Circles Review Set A (Chapter 2) Review Set B (Chapter 2) Review Set C (Chapter 2) 44 48 52 58 59 63 65 67 70 71 72 (42) 73 (67) 74 78 81 84 86 88 90 91 (68) A B C D E F G H I J 2 NUMBER FACTS cyan Y:\...\SA_06-2\SA06_00\004SA600.CDR Wed Sep 24 11:47:49 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 Addition and subtraction Multiplication and division by powers of 10 Calculator use Multiplication Division Using number operations (problem solving) Zero and one Factors of whole numbers 75 0 5 95 100 50 75 25 A B C D E F G H 0 Different number systems How many? The language of number A numbered world Our number system Zero Rounding numbers Estimation and approximation Place value Number line Number puzzles (Extension) Review Set A (Chapter 1) Review Set B (Chapter 1) Review Set C (Chapter 1) 25 3 5 Numbers in brackets denote pages in the first edition. They have been included to assist teachers using the first and second editions in the same classroom. black (13) (15) (15) (18) (19) (22) (30) (35) (37) (47) (51) (57) (58) (60) (62) (70) (73) (76) (76) (81) (86) SA_06 Color profile: Disabled Composite Default screen TABLE OF CONTENTS I Divisibility J Multiples of whole numbers K One operation after another Review Set A (Chapter 3) Review Set B (Chapter 3) Review Set C (Chapter 3) Extension (A different base system) 4 FRACTIONS A B C D E F G H I J K L M DECIMALS cyan Y:\...\SA_06-2\SA06_00\005SA600.CDR Wed Sep 24 12:10:56 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 Representing decimals Using a number line Showing place value with blocks Place value Value of money Adding decimal numbers Subtracting decimal numbers Multiplying & dividing by 10, 100 and 1000 Converting fractions to decimals Converting decimals to fractions Percentage Multiplication with whole numbers Division by whole numbers Operating with money Problem solving 95 50 75 25 0 5 95 100 50 75 25 0 5 A B C D E F G H I J K L M N O 100 5 Fractions Representation of fractions Fractions of regular shapes Fractions of quantities Finding the whole from a fraction Ordering of fractions Equivalent fractions Fractions to lowest terms Mixed numbers & improper fractions Adding fractions Subtraction of fractions Miscellaneous problem solving Ratio Review Set A (Chapter 4) Review Set B (Chapter 4) Review Set C (Chapter 4) black 5 93 94 96 98 98 99 100 (89) 101 (123) 102 103 104 105 109 110 111 115 115 118 123 125 126 129 130 131 (124) 133 (155) 134 135 137 138 143 146 149 151 154 156 156 158 162 164 165 (156) (91) (84) (125) (126) (128) (131) (133) (134) (140) (147) (151) (154) (142) (157) (159) (161) (165) (168) (170) (172) (175) (177) (179) (183) SA_06 Color profile: Disabled Composite Default screen 6 TABLE OF CONTENTS P Rounding decimal numbers Review Set A (Chapter 5) Review Set B (Chapter 5) Review Set C (Chapter 5) 6 MEASUREMENT A B C D E F G H I J K L M N 7 Scales Grids Maps Direction Plans Coordinates Locus Review Set A (Chapter 7) Review Set B (Chapter 7) cyan Y:\...\SA_06-2\SA06_00\006SA600.CDR Wed Sep 24 12:17:12 2003 (100) (106) (109) (111) (115) (117) 207 (187) 209 210 212 216 221 224 227 229 229 (189) yellow 95 100 50 75 25 0 234 235 240 244 245 248 253 5 95 100 50 75 25 0 5 95 50 100 magenta (96) (190) (191) (195) (198) (200) 231 Polyhedra Drawing solids Making solids from nets Different views of objects Intersection of solids and planes Mass Review Set A (Chapter 8) 75 0 5 95 100 50 75 172 174 176 180 182 183 185 186 188 192 193 194 197 200 203 204 205 SOLIDS AND MASS A B C D E F 25 Units of measure Converting length units Perimeter Perimeters of special figures Problem solving with perimeters Comparing area units Area Metric area units Area of a rectangle Areas of composite shapes Problem solving with areas Volume Capacity Calculating volumes and capacities Review Set A (Chapter 6) Review Set B (Chapter 6) Review Set C (Chapter 6) 25 8 0 171 LOCATION AND POSITION A B C D E F G 5 166 168 169 169 black (212) (214) (220) (223) (224) SA_06 Color profile: Disabled Composite Default screen TABLE OF CONTENTS Review Set B (Chapter 8) Review Set C (Chapter 8) A B C D E F TIME AND TEMPERATURE A B C D E F G H I PATTERNS AND ALGEBRA Y:\...\SA_06-2\SA06_00\007SA600.CDR Wed Sep 24 11:48:46 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 Number patterns (sequences) Dot patterns Matchstick patterns Rules and problem solving Graphing patterns Using word formulae Converting words to symbols Using a spreadsheet Algebraic expressions Graphing from a rule Graphs of real world situations Review Set A (Chapter 11) Review Set B (Chapter 11) 0 50 75 25 0 5 95 100 50 75 25 0 A B C D E F G H I J K cyan Time lines Units of time A date with a calendar Reading clocks and watches Clockwise direction Timetables Speed Temperature Maximum, minimum and average temperatures Review Set A (Chater 10) Review Set B (Chapter 10) Review Set C (Chapter 10) 5 11 Sampling Organising data Displaying data Using technology to graph data Interpreting data Measuring the 'middle' of a data set Review Set A (Chapter 9) Review Set B (Chapter 9) Review Set C (Chapter 9) 95 10 5 253 254 DATA COLLECTION AND REPRESENTATION 100 9 7 black 255 257 257 262 272 275 277 280 281 282 (275) 283 (249) 285 287 291 294 302 303 306 308 310 312 313 314 (251) 315 (291) 316 317 319 321 323 323 326 328 329 332 335 336 337 (292) (275) (279) (282) (284) (252) (257) (259) (266) (268) (293) (295) (296) (298) (299) (301) (303) (304) SA_06 Color profile: Disabled Composite Default screen 8 TABLE OF CONTENTS 12 TRANSFORMATIONS A B C D E 13 CHANCE AND PROBABILITY 340 343 346 349 356 359 360 361 (312) 363 (341) 364 367 372 373 374 376 378 379 380 (342) cyan Y:\...\SA_06-2\SA06_00\008SA600.CDR Wed Sep 24 12:45:53 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 415 5 INDEX 95 381 100 50 Describing chance All possible results Probability Most likely to least likely order Statistics and probability Life insurance tables (Extension) Review Set A (Chapter 13) Review Set B (Chapter 13) Review Set C (Chapter 13) (311) ANSWERS 75 25 0 A B C D E F 5 The language of transformations Tessellations Line symmetry Rotations Enlargements and reductions Review Set A (Chapter 12) Review Set B (Chapter 12) Review Set C (Chapter 12) 339 black (332) (316) (321) (327) (344) (349) (350) (351) SA_06 Color profile: Disabled Composite Default screen Chapter 1 Whole numbers ···································· Knowledge, skills and understandings In this chapter you will learn how to ! ! ! ! ! recognise the existence of different number systems (e.g. Greek, Roman, HinduArabic) provide examples of the use of number in everyday life read, write and record numbers to one million, using numerals and words explain place value of digits in numbers to 1¡000¡000 ! ! ! write numbers to 1¡000¡000 in expanded form round to the nearest 10, 100, 1000, 10¡000 and 100¡000 place numbers in descending and ascending order compare numbers and use symbols (e.g., = , = 6 , < and >) cyan Y:\...\SA_06-2\SA06_01\009SA601.CDR Mon Sep 29 13:45:19 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 ·················································· black SA_06 Color profile: Disabled Composite Default screen 10 WHOLE NUMBERS (CHAPTER 1) A DIFFERENT NUMBER SYSTEMS The number system we use is called the Hindu-Arabic System. Archaeologists and anthropologists study ancient civilizations. They have helped us to understand how people long ago counted and recorded numbers. Before the Hindu-Arabic system many ancient number systems were used to tally. For example, items they wanted to show could be represented or matched by: scratches on a cave wall (show new moons since the buffalo herd came through) knots on the rope (show rows of corn planted) pebbles on sand (show traps set for fish) notches cut on the branch (show new lambs born). © and © © © © was much easier for tallying A tally of jjjjj eventually was replaced by © jjjj jjjj jjjj than jjjjjjjjjj: To us now, this would not seem to be a very efficient way for recording larger numbers. The Ancient Egyptians developed the symbol to show jjjjjjjjjj and to represent ten lots of or 100. The Mayans used a to represent , ..... to represent ..... and to represent 100. ANCIENT GREEK OR ATTIC SYSTEM cyan Y:\...\SA_06-2\SA06_01\010SA601.CDR Wed Sep 24 14:13:11 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 Like the Mayans, the Ancient Greeks could see the need to include a symbol for 5. Some examples of Ancient Greek numbers are black SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) 1 2 3 4 20 30 700 1000 5 50 6 7 8 60 100 9 10 400 500 11 Can you see what the smaller D, H, and X symbols do to the symbol when they are joined? 5000 This system depends on addition and multiplication. Example 1 Change the following Ancient Greek numerals into a Hindu-Arabic number: a b a b 1000 6000 300 700 20 80 + 4 1324 + 1 6781 EXERCISE 1A 1 Change the following Ancient Greek numerals into Hindu-Arabic numbers: a b c d e f 2 Write the following Hindu-Arabic numbers as Ancient Greek numerals: a 14 b 31 c 99 d 555 e 4082 f 5601 ROMAN NUMERALS Like the Ancient Greeks, the Romans also had a system which used a combination of symbols. The first four numbers could be represented by the fingers on one hand. I II III IIII but later IV cyan Y:\...\SA_06-2\SA06_01\011SA601.CDR Wed Sep 24 12:49:04 2003 magenta 95 100 50 75 25 0 95 50 75 25 0 100 yellow 5 4 3 5 95 100 50 2 75 25 0 5 95 100 50 75 25 0 5 1 black SA_06 Color profile: Disabled Composite Default screen 12 WHOLE NUMBERS (CHAPTER 1) The V formed by the thumb and forefinger of Look for Roman numerals on clocks and watches, at the end of movies when the credits are being shown, on plaques and on the top of buildings, and as chapter numbers to novels. represented 5. an open hand Two V’s joined together of 5, i.e., ten or X. became two lots C represented one hundred, and half of i.e., L became 50. , One thousand was represented by an . With a little imagination you should see that an split in half and turned 90o would look like a , so D became half a thousand or 500. 1 I 2 II 3 III 20 XX 30 XXX 4 IV 40 XL 50 L 5 V 6 VI 7 VII 8 VIII 60 LX 70 LXX 80 LXXX 9 IX 90 XC 10 X 100 C 500 D 1000 M Unlike some other ancient systems, the Roman system had to be written in order and the value would change if the order changed. For example, whereas and whereas IV stands for 1 before 5, i.e., 4 VI stands for 1 after 5, i.e., 6 XC stands for 10 before 100, i.e., 90 CX stands for 10 after 100, i.e., 110. There were also rules for the order in which symbols could be used. The I could only appear before V or X, the X could only appear before L or C, and C could only appear before a D or an M. For example, the number 1999 could be written as MCMXCIX, but could not be written as MIM. Larger numerals were formed by placing a stroke above the symbol which made the number 1000 times as large: 5000 V 10 000 X 50 000 L 100 000 C 500 000 D 1 000 000 M EXERCISE 1A (continued) 3 What numbers are represented by the following symbols: a XVI b XXXI d CXXIV e MCCLVII cyan Y:\...\SA_06-2\SA06_01\012SA601.CDR Wed Sep 24 12:50:17 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 4 Write the following numbers in Roman numerals: a 18 b 34 c 279 d 902 black c f LXXXIII D L VDCC? e 1046 f 2551 SA_06 Color profile: Disabled Composite Default screen 13 WHOLE NUMBERS (CHAPTER 1) a Which Roman numeral less than one hundred has the greatest number of symbols? 5 b What is the highest Roman numeral between M and MM which has the least number of symbols? Denarii is the unit c Write the year 1999 using Roman symbols. of currency used by the Romans. 6 Use Roman numerals to answer the following questions. a Each week Octavius sharpened CCCLIV swords for the General. How many would he need to sharpen if the General doubled his order? b What would it cost Claudius to finish his courtyard if he needed to pay for CL pavers at VIII denarii each and labour costs of XCIV denarii? c In one week beginning on Monday and ending on Saturday, Marcus baked LXVIII, LVI, XLIV, XLIX, XCVIII and CLIV loaves. i How many loaves did he bake for the week? ii What was his profit if he made III denarii profit on each loaf? d Julius and his road building crew were expected to build MDC metres of road before the end of spring. If they completed CCCLX metres in summer, CDLXXX in autumn, and CCCXV in winter, how much more did they need to complete in the last season? RESEARCH OTHER WAYS OF COUNTING Find out 1 How the Ancient Egyptians and Mayans represented numbers larger than 1000. 2 Whether the Egyptians used a symbol for zero. 3 How to write the symbols 1 to 10 using Chinese or Japanese characters. 4 What larger Braille numbers feel like. 5 How deaf people ‘sign’ numbers. 6 What the Roman numerals were for the two Australian Olympiads. 1 2 3 4 5 6 7 8 9 0 INVESTIGATION BIRTHDAYS IN ROMAN What to do: Use a calendar to help you. cyan Y:\...\SA_06-2\SA06_01\013SA601.CDR Wed Sep 24 12:50:46 2003 magenta yellow XX XXVII 95 iv 100 50 VI XIII 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 1 In Roman numerals write: a your date of birth, for example, XXI-XI-MCMXLVI b what the date will be when you are iii XXI i XV ii L black I VII XIV XXI XXVII VIII XV XXII I XX IX II IX XVI XXIII III X XVII XXIV IV XI XVIII XXV V XII XIX XXVI C SA_06 Color profile: Disabled Composite Default screen 14 WHOLE NUMBERS (CHAPTER 1) 2 Ignoring any leap year what will be the date: a XIV days after your XVI birthday b LX days after your XIX birthday? B HOW MANY? THE LANGUAGE OF NUMBER Some people think that mathematics is just working with numbers. Mathematics is more than just working with numbers. Mathematics has symbols and language besides numbers. Numbers also have a language of their own. The following are examples of how number has developed its own language to tell us “how many”: two apples a couple of people a brace of ducks a dyad a pair of sox twins a double a duet Three people playing musical instruments or singing together are a trio. In cricket, a bowler getting three batsmen out in three successive balls is said to have bowled a hat trick. Writing an order in triplicate means that three copies of the order form are made. Usually each form is a different colour. Some other words meaning three include: thrice, triad, trilogy, triple, and trifecta. ACTIVITY WORDS FOR NUMBERS What to do: cyan Y:\...\SA_06-2\SA06_01\014SA601.CDR Wed Sep 17 12:20:43 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 1 In groups, brainstorm a list of as many words as you can which can mean four or five. Check your list for the correct spelling and meanings using a dictionary or thesaurus. black SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) 15 a Use dictionaries and thesauri (more than one thesaurus) to find what number is represented by the following words: octave, dozen, duck, decade, score, naught, century, zilch, gross, ton, hexagon, zero, quadruplet, quartet, hexahedron, pentathlon, nonet, quintet, quinella, heptagon, pentahedron, grand, sextet. b Write sentences using these words to illustrate numbers. 2 3 Use the ideas from Exercise 1A to write half a dozen questions to challenge your class mates. EXERCISE 1B 1 How much did each twin get when they shared equally a seven hundred and fifty dollar prize? 2 Each member of the string quartet played a solo for a minute and a half at the concert. What amount of time was played by soloists? 3 The trio travelling around the country each paid $125:50 for petrol and motel accommodation. What was the total amount paid? 4 The septuagenarian (person in their 70’s) celebrated her birthday with a cake which had a candle for each decade she had lived. How many candles were on her cake? 5 Sir Donald Bradman scored 78 tons and 36 double centuries during his first class cricket career. What was the smallest total number of runs he may have scored just in tons and double centuries? 6 The quintet each trebled their $400 investment. What was their new total amount? C A NUMBERED WORLD Besides the numbers that we use at school, numbers have many other uses. For example, you will find an ISBN number near the front of this book. This 10 digit International Standard Book Number is a record of the language in this book. This number also tells the place where it was written and who the publisher was. cyan Y:\...\SA_06-2\SA06_01\015SA601.CDR Wed Sep 17 12:24:47 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 Your birth certificate will have a number on it. You have an enrolment number for the school you are attending. Your address, telephone, bus route and shoe size all have numbers. black 715 896 772 323 260 379 104 694 417 099 915 341 993 944 641 232 CRED IT C ARD 558 485 500 973 801 564 442 385 687 594 667 185 788 236 727 251 803 222 418 80354192 37 87246 004 309 55 35 JOH681 55 1600 N CI390 582 751 955 660 441 TIZEN204 /02 123 324 924 871 916 500 86407791 437 256 005 081 072 775 276 510 234 240 758 247 081 714 797 128 020 284 647 317 371 074 422 745 ISBN 1-876543-00-0 256 477 391 628 302 672 851 185 906 854 522 688 389 396 421 819 961 367 677 716 644 657 086 398 346 024 253 141 456 775 211 744 140 278 283 653 127 988 721 310 9 781876 543006 > 997 794 681 582 081 040 199 242 030 819 023 127 526 990 408 718 389 994 657 891 874 603 309 257 SA_06 Color profile: Disabled Composite Default screen 16 WHOLE NUMBERS (CHAPTER 1) ACTIVITY USING NUMBERS What to do: 1 In groups, brainstorm as many uses of number as you can for the following categories: a b money c travel information d records. 2 Find out how a bar code works and how it is used. D OUR NUMBER SYSTEM From our brief look at the History of Number, you would remember that the method of writing numbers is called a number system. The system we use was developed in India, 2000 years ago, and was introduced to European nations by Arab traders about 1000 years ago. We therefore call our system the Hindu-Arabic System. The marks we use to represent numbers are called numerals. They are made up by using the symbols 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0. These symbols are called digits. ordinal number one two three four five six seven eight nine 1 2 3 4 5 6 7 8 9 Hindu-Arabic Numeral our numeral The digits 3 and 8 can be used to form the numeral ‘38’ for number ‘thirty-eight’ and numeral ‘83’ for number ‘eighty-three’. In Latin “numerus” means number. The numbers we use for counting are called natural numbers. The possible combination of natural numbers is endless. There is no largest number. We say that the set of all natural numbers is infinite. Natural numbers are also called counting numbers. There are three kinds of people in the world. Those who can count and those who cannot. Most of the time we are not worried about the difference between ‘numeral’ and ‘number’. We use the word number most of the time. cyan Y:\...\SA_06-2\SA06_01\016SA601.CDR Wed Sep 17 13:47:19 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 If we include in our set of numbers the number zero, 0, then our set now has a new name, the set of whole numbers. black SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) 17 There are three features which make the Hindu-Arabic system useful and more efficient than most ancient systems: ² It uses only 10 digits to make all the natural numbers. ² It uses the digit 0 or zero to show an empty space. ² It has a place value system where digits represent different numbers when placed in different value columns. un 5 2 6 7 9 4 its hu thondre us d ten ands th o us an ds th o us an ds hu nd red s ten s Each digit in a number has a place value. For example: in 567 942 Example 2 What number is represented by the digit 9 in the numeral 1972? nine hundred or 900 EXERCISE 1D 1 What number is represented by the digit 7 in the following? a 27 b 74 c 567 e 1971 f 7635 g 3751 i 80 007 j 72 024 k 87 894 d h l 758 27 906 478 864 2 What is the place value of the digit 5 in the following? a 385 b 4548 c 32 756 d 577 908 3 Write down the place value of the 2, the 4 and the 8 in each of the following: a 1824 b 32 804 c 80 402 d 248 935 a Use the digits 9, 5 and 7 once only to make the smallest number you can. b Write the largest number you can, using the digits 3, 2, 0, 9 and 8 once only. c What is the largest 6 digit number you can write using each of the digits 1, 4 and 7 twice? d What are the different numbers you can write using the digits 6, 7 and 8 once only? 4 cyan Y:\...\SA_06-2\SA06_01\017SA601.CDR Wed Sep 17 12:46:03 2003 magenta yellow 95 100 50 75 25 0 5 100 95 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 5 Place the following numbers in order beginning with the smallest (ascending order): a 62, 26, 20, 16, 60 b 67, 18, 85, 26, 64, 29 c 770, 70, 700, 7, 707 d 2808, two thousand and eight, 2080, two thousand eight hundred black SA_06 Color profile: Disabled Composite Default screen 18 WHOLE NUMBERS (CHAPTER 1) 6 Place the following numbers in order beginning with the largest (descending order): a 17, 21, 20, 16, 32 b 77, 28, 95, 36, 64, 49 c 880, 800, 80, 808, 8 d 2606, two thousand and six, 2060, two thousand six hundred 7 Often the symbols we use in mathematics are used instead of a group of words (called a phrase). Examples are: = > 6= < means is equal to means is greater than means is not equal to means is less than Rewrite the following with the symbol or symbols =, 6=, > or < to replace the ¤ to make a correct statement: a 7¤9 b 9¤7 c 2+2 ¤ 4 d 3¡1 ¤ 9¡7 e 6+1 ¤ 5 f 7¡3 ¤ 9¡5 g 16 ¤ 5 h 5 ¤ 16 ¡ 9 i 12 ¤ 24 ¥ 2 j 11 £ 2 ¤ 44 ¥ 2 k 15 ¡ 9 ¤ 2 £ 3 l 7 + 13 ¤ 5 £ 4 m 118 ¡ 17 ¤ 98 + 3 n 7900 ¤ 9700 o 7900 ¤ 7090 p 25 £ 4 ¤ 99 q 99 ¤ 25 £ 4 r 345 678 ¤ 345 687 Example 3 a b Express 5 £ 10 000 + 7 £ 1000 + 9 £ 100 + 4 in simplest form. Write 3908 in expanded form. a 5 £ 10 000 + 7 £ 1000 + 9 £ 100 + 4 = 57 904 b 3908 = 3 £ 1000 + 9 £ 100 + 8 8 Express the following in simplest form: a 4 £ 10 + 9 b 7 £ 100 + 4 c 3 £ 100 + 8 £ 10 + 6 d 2 £ 1000 + 6 £ 100 + 3 £ 10 + 4 e 6 £ 10 000 + 5 £ 100 + 8 £ 10 + 3 f 9 £ 10 000 + 3 £ 1000 + 8 g 3 £ 100 + 4 £ 10 000 + 7 £ 10 + 6 £ 1000 + 5 h 2 £ 10 + 9 £ 100 000 + 8 £ 1000 + 3 i 2 £ 100 000 + 3 £ 100 + 7 £ 10 000 + 8 cyan Y:\...\SA_06-2\SA06_01\018SA601.CDR Mon Sep 29 12:18:55 2003 magenta yellow 95 2438 400 308 100 50 75 25 0 5 95 c g 100 50 75 340 39 804 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 9 Write in expanded form: a 486 b e 24 569 f black DEMO d h 4083 254 372 SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) 19 Example 4 a Write “two thousand seven hundred and four” in numeral form. b Write the numeral 36 098 in words. a 2704 b thirty six thousand and ninety eight 10 Write the following in numeral form: a thirty six b seventy c thirty d eighteen e nine hundred f nine thousand g five hundred and twenty h five hundred and two i six thousand and fourteen j six thousand four hundred and forty k fourteen thousand and four l forty thousand and forty m fifteen thousand eight hundred and sixty nine n ninety five thousand three hundred and eleven o seven hundred and eight thousand one hundred and ninety eight. 11 Write a e i m the following numbers in words: 66 b 660 4389 f 6010 15 040 j 44 444 50 500 n 505 000 c g k o 715 90 000 408 804 500 500 d h l p 888 38 700 246 357 50 050 12 Write the following operations and their answers in numerical form: a four more than forty b six greater than eleven c three less than two hundred d eight fewer than eighty e eighteen fewer than six thousand f three thousand reduced by two hundred g an additional fifty to eleven thousand h 38 more than five hundred and nine thousand E ZERO Neither the Egyptians nor the Romans had a symbol to represent nothing. The symbol 0 was called zephirum in Arabic. Our word zero comes from this. cyan Y:\...\SA_06-2\SA06_01\019SA601.CDR Wed Sep 17 13:00:23 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 In the Hindu-Arabic System, the digit for zero is used as a place holder in numerals. black SA_06 Color profile: Disabled Composite Default screen 20 WHOLE NUMBERS (CHAPTER 1) For example, in 580 the 0 is a place holder for units to show that the 8 means 8 tens and there are no single units. Also, in the number 6032 the 0 shows that there are no hundreds. However, because of the place that the zero takes, the digit to the left of it takes on the value of ‘thousands’. Example 5 In the number 789 place the zero digit between 7 and 8. a Write the new number. b Write the new number in words. With whole numbers the zero is never placed before any other digit, unless there is a very special reason. a 7089 b seven thousand and eighty nine EXERCISE 1E 1 With the number 543: a i place a zero between the 4 and 3 ii write the new number in words ii write the new number in words b i place two zeros between the 5 and 4 c i ii place a zero between the 5 and 4 and two zeros between the 4 and 3 write the new number in words d i place two zeros after the 3 e i ii place two zeros between the 5 and the 4 and three zeros after the 3 write the new number in words f ii write the new number in words Place four zeros in the number, and by rearranging the digits, write the five highest numbers you can make. Start with the highest. cyan Y:\...\SA_06-2\SA06_01\020SA601.CDR Wed Sep 17 13:29:19 2003 magenta yellow 95 100 50 75 25 0 5 5 ¥ 0 has no answer. 95 Example: 100 ² Any number ¥ 0 has no answer 50 0¥9=0 75 Example: 25 ² 0 ¥ any number = 0 0 7£0=0 5 Example: 95 ² Any number £ 0 = 0 100 8¡0=8 50 Example: 75 ² Any number ¡ 0 = the same number 25 3+0=3 0 Example: 5 95 ² Any number + 0 = the same number 100 50 75 25 0 5 The rules for operating with zero are: black SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) F 21 ROUNDING NUMBERS Often we are not really interested in the exact value of a number, but rather we want a reasonable estimate of it. For example, there may be 48 students in the library or 315 competitors at the athletics carnival or 38 948 spectators at the football match. If we are only interested in an approximate number, then 50 students, 300 competitors and 40 000 spectators would be a good approximation in each of the above examples. We may round off numbers by making them into, for example, the nearest number of tens. 368 is roughly 37 tens or 370 363 is roughly 36 tens or 360 We say 368 is rounded up to 370 and 363 is rounded down to 360. Rules for rounding off are: ² If the digit after the one being rounded off is less than 5 (i.e., 0, 1, 2, 3 or 4) we round down. ² If the digit after the one being rounded off is 5 or more (i.e., 5, 6, 7, 8, 9) we round up. Example 6 DEMO Round off the following to the nearest 10: a 38 b 483 c 8605 a 38 is approximately 40 fRound up, as 8 is greater than 5g b 483 is approximately 480 fRound down as 3 is less than 5g c 8605 is approximately 8610 fRound up, halfway is rounded upg EXERCISE 1F cyan Y:\...\SA_06-2\SA06_01\021SA601.CDR Wed Sep 17 13:43:01 2003 magenta yellow 95 100 50 75 c g k o 25 0 5 95 65 561 2856 9995 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 1 Round off to the nearest 10: a b 23 e 347 f i 3015 j m 2895 n black 68 409 3094 30 905 d h l p 97 598 8885 49 895 SA_06 Color profile: Disabled Composite Default screen 22 WHOLE NUMBERS (CHAPTER 1) Example 7 DEMO Round off the following to the nearest 100: a 89 b 152 c 19 439 a 89 is approximately 100 fRound up as 8 is greater than 5g b 152 is approximately 200 fRound up for 5 or moreg c 19 439 is approximately 19 400 fRound down, as 3 is less than 5g Go first to the digit after the one being rounded off. That is, the first one to the right. 2 Round off to the nearest 100: a 81 b 671 e 349 f 982 i 999 j 13 484 c g k 617 2111 99 199 d h l 850 3949 10 074 Example 8 DEMO Round off the following to the nearest 1000: a 932 b 4500 c 44 482 a 932 is approximately 1000 fRound up as 9 is greater than 5g b 4500 is approximately 5000 fRound up for 5 or moreg c 44 482 is approximately 44 000 fRound down, as 4 is less than 5g 3 Round off to the nearest 1000: a 834 b 695 e 7800 f 6500 i 13 095 j 7543 c g k 1089 9990 246 088 d h l 5485 9399 499 359 Example 9 cyan Y:\...\SA_06-2\SA06_01\022SA601.CDR Mon Sep 29 12:19:22 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 fRound up for 5 or moreg 25 99 981 is approximately 100 000 0 c 5 fRound down for 0g 95 60 895 is approximately 60 000 100 b 50 fRound down as 2 is less than 5g 75 42 145 is approximately 40 000 25 0 a 5 95 100 50 75 25 0 5 Round off the following to the nearest 10 000: a 42 635 b 60 895 c 99 981 black SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) 23 4 Round off to the nearest 10 000: 18 124 89 888 a e 47 600 52 749 b f c g 54 500 90 555 Example 10 d h 75 850 99 776 DEMO Round off the following to the nearest 100 000: a 124 365 b 350 984 c 547 690 a 124 365 is approximately 100 000 fRound down as 2 is less than 5g b 350 984 is approximately 400 000 fRound up for 5 or moreg c 547 690 is approximately 500 000 fRound down as 4 is less than 5g 5 Round off to the nearest 100 000: a 181 000 b 342 000 e 139 888 f 450 749 c g 654 000 290 555 d h 709 850 89 512 6 Round off to the accuracy given: a $187:45 (to nearest $10) One kilolitre is one thousand litres. b $18 745 (to nearest $1000) c 375 km (to nearest 10 km) d $785 (to nearest $100) e the population of a town is 29 295 (to nearest one thousand) f 995 cm (to nearest metre) g 8945 litres (to nearest kilolitre) h the cost of a house was $274 950 (to nearest $10 000) i the number of sheep on a farm is 491 560 (nearest 100 000) RESEARCH ROUNDING AROUND YOU What to do: Check around your home, class and school to find the following and then round off to the accuracy asked for. 1 To the nearest 10, find the number of a pieces of cutlery in your home b i pencils ii exercise books in your classroom c adults in the school d vehicles in the school carpark. A few pages further on in this chapter you will find examples of how to estimate a number. cyan Y:\...\SA_06-2\SA06_01\023SA601.CDR Wed Sep 17 14:00:23 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 2 To the nearest 100, find the number of a students in the school b items sold in the canteen each day c books in the school library d bricks in a house closest to your school. black SA_06 Color profile: Disabled Composite Default screen 24 WHOLE NUMBERS (CHAPTER 1) 3 To the nearest 1000, find the number of a kilometres your family car has travelled b kilolitres of water your household used last year c pages in the Yellow Pages d digits in all the phone numbers on a typical page in the White Pages. 4 To the nearest 100 000, find a the size of the crowd of last year’s biggest outdoor event b the cost of the dearest house in Sunday’s Real Estate pages of the newspaper. G ESTIMATION AND APPROXIMATION Calculators and computers are part of everyday life. They save lots of time, energy and money by the speed and accuracy with which they complete different operations. Three double beef burgers and fries... $175 thanks! However, the people operating the computers and calculators can, and do, make mistakes when keying in the information. It is very important that when we use calculators we have a strategy for making an estimate of what the answer should be. An estimate is not a guess. It is a quick and easy approximation to the correct answer. Not likely! By making an estimate we can tell if our calculated or computed answer is reasonable. ROUNDING TO THE NEAREST 5 CENTS Because we no longer use 1 cent and 2 cent coins, amounts of money to be paid in cash must be rounded to the nearest 5 cents. For example, a supermarket bill and the bill for fuel at a service station must be rounded to the nearest 5 cents. cyan Y:\...\SA_06-2\SA06_01\024SA601.CDR Wed Sep 17 14:15:08 2003 magenta yellow 95 100 50 75 25 50 0 25 amount remains unchanged. amount is rounded down to 0. amount is rounded up to 5. amount is rounded down to 5. amount is rounded up to 10. 5 the the the the the 95 5, 2, 4, 7, 9, 100 or or or or or 75 0 1 3 6 8 0 95 100 50 75 25 0 5 95 100 50 75 25 0 5 ² ² ² ² ² 5 If the number of cents ends in black SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) 25 Example 11 Round the following amounts to the nearest 5 cents: a $1:42 b $12:63 c $3:16 a d $24:99 $1:42 would be rounded down to $1:40: 2 is rounded down. b $12:63 would be rounded up to $12:65. DEMO 3 is rounded up to 5. c $3:16 would be rounded down to $3:15. 6 is rounded down to 5. d $24:99 would be rounded up to $25:00: 9 is rounded up to 10, so 99 becomes 100 and $24:99 becomes $25:00 EXERCISE 1G 1 Round the following amounts to the nearest 5 cents: a 99 cents b $2:74 c $1:87 e $34:00 f $25:05 g $16:77 i $13:01 j $102:23 k $430:84 2 d h l $1:84 $4:98 $93:92 a Rachel paid cash for her supermarket bill of $84:72. How much did she pay? b Jason filled his car with petrol and the amount shown at the petrol pump was $31:66. How much did he pay in cash? c Nicolas used the special dry-cleaning offer of ‘3 items for $9:99’. How much money did he pay? For the purposes of estimation, money is rounded to the nearest whole dollar. Amounts between $1:00 and $1:49 are rounded to one dollar and amounts $1:50 and up to $1:99 are rounded to $2:00. Example 12 a $4:37 Approximate b $16:85 to the nearest dollar. a $4:37 is rounded down to $4:00 f37 cents is less than 50 centsg b $16:85 is rounded up to $17:00 f85 cents is greater than 50 centsg cyan Y:\HAESE\SA_06\SA06_01\025SA601.CDR Tue Aug 26 11:50:03 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 3 For the purpose of estimation, round the following to the nearest whole dollar: a $3:87 b $9:28 c $4:39 d $11:05 e $7:55 f $19:45 g $19:55 h $39:45 i $39:50 j $61:19 black SA_06 Color profile: Disabled Composite Default screen 26 WHOLE NUMBERS (CHAPTER 1) When estimating sums, products, quotients and differences we usually round the first digit (from the left) and put zeros in other places. For example Rounding to the first digit means the same as rounding to one figure. 68 would round to 70 374 would round to 400 5396 would round to 5000 and 43 875 would round to 40 000 Example 13 Estimate the cost of 28 chocolates at $1:95 each. 28 £ 1:95 is approximately 30 £ $2 is approximately $60 4 Ice block $0.85 Cheese snacks $1.30 300mL drink $1.15 Crisps $1.05 Pineapple lumps $1.80 Licorice rope $0.75 Icecream $2.10 Jubes $1.20 Honeycomb bar $0.95 Health bar $1.95 Chocolate bar $1.30 cyan Y:\...\SA_06-2\SA06_01\026SA601.CDR Mon Sep 29 13:52:30 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 Estimate the total cost (by rounding the prices to the nearest dollar) of a one icecream, a packet of crisps, a health bar and a drink b 5 licorice ropes, 4 icecreams, 2 honeycomb bars and 4 drinks c 3 ice blocks, 2 pkts pineapple lumps, 4 chocolate bars and 3 cheese snacks d 10 health bars, 4 icecreams, 6 jubes and 3 licorice ropes e 19 ice blocks, 11 drinks, 12 pkts cheese snacks and 9 pkts pineapple lumps f 21 pkts crisps, 18 choc bars, 28 health bars and 45 drinks g 4 dozen drinks, half a dozen packets of pineapple lumps and a dozen health bars h 192 honeycomb bars, 115 icecreams, 189 pkts crisps and 237 drinks i 225 licorice ropes, 269 drinks, 324 honeycomb bars and 209 ice blocks. black SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) ACTIVITY 27 SHOPPING AROUND What to do: 1 Estimate how many of each of the items in the table you can buy for $20 000. PRINTABLE · Use only the cheapest prices and brand new items. TEMPLATE · You cannot buy a fraction of an item. Write your estimate in the chart. Check your estimate through advertisements in newspapers and catalogues. Complete the following chart. 2 3 4 A B Estimated number you could buy Item C Price from catalogue or newspaper D Price rounded to one figure E Correct number of items bought. Divide $20 000 by D F Balance or amount left from $20 000 lap top computer colour printer 109 cm screen TV return air fares to Disneyland wheel size 26 mountain bikes microwave oven basketball 5 6 Write down the names of the items in order from most to least expensive. If you bought one of each of the above items, how much change would you have from $20 000? Example 14 Estimate the sum 594 + 317 + 83 cyan Y:\HAESE\SA_06\SA06_01\027SA601.CDR Mon Aug 25 11:26:21 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 Round off to the first digit then put zeros in the other places: 594 + 317 + 83 is approximately 600 + 300 + 80 which is approximately 980 black SA_06 Color profile: Disabled Composite Default screen 28 WHOLE NUMBERS (CHAPTER 1) Example 15 Estimate the difference 2164 ¡ 897 Round off to the first digit then put zeros in the other places: 2164 ¡ 897 is approximately 2000 ¡ 900 which is approximately 1100 EXERCISE 1G (continued) 5 Estimate the following: a 78 + 42 d 83 + 61 + 59 g 3189 + 4901 j 89 139 ¡ 31 988 478 + 242 834 + 615 + 592 6497 ¡ 2981 59 104 + 20 949 b e h k c f i l 196 + 324 815 ¡ 392 34 614 ¡ 19 047 1489 + 2347 + 6618 Go back over the above exercises and compare your estimates with the exact answers. 6 For 5 a, c, e, g, i and k, show the difference between the estimate and the exact answer. Example 16 Estimate the product a 39 £ 7 b 891 £ 4 a Round off to the first digit then put zeros in the other places 39 £ 7 is approximately 40 £ 7 which is approximately 280 b Round off to the first figure then put zeros in other places 891 £ 4 is approximately which is approximately 7 Estimate the following products: a 19 £ 8 b 31 £ 7 e 87 £ 5 f 92 £ 3 i 54 £ 7 j 36 £ 9 c g k 900 £ 4 3600 28 £ 4 39 £ 9 94 £ 5 d h l 52 £ 6 88 £ 8 67 £ 3 cyan Y:\HAESE\SA_06\SA06_01\028SA601.CDR Fri Aug 29 16:25:42 2003 magenta yellow 95 100 50 75 25 0 38 £ 3 5 h 95 82 £ 5 100 g 50 69 £ 8 75 f 25 27 £ 6 0 e 5 92 £ 9 95 d 100 53 £ 4 50 c 75 78 £ 7 25 b 0 41 £ 9 5 95 a 100 50 75 25 0 5 8 Multiply the following. Use estimation to check that your answers are reasonable: black SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) 9 Estimate the products: a 484 £ 3 e 729 £ 8 197 £ 9 381 £ 4 b f c g 521 £ 6 2158 £ 7 d h 29 238 £ 8 3948 £ 5 10 Multiply the following. Use estimation to check that your answers are reasonable: a 214 £ 9 b 694 £ 3 c 808 £ 7 d 376 £ 8 e 497 £ 6 f 941 £ 4 g 522 £ 5 h 658 £ 7 i 374 £ 4 j 783 £ 5 k 413 £ 9 l 863 £ 7 Example 17 Estimate the product 427 £ 89 Round off the first digit then put zeros in the other places: 427 £ 89 is approximately 400 £ 90 f5 digits in the questiong is approximately 36 000 f5 digits in the answerg The estimate tells us that the correct answer should have 5 digits in it. The sum of the number of zeros is the number of zeros which should appear in the product, unless the product of the two digits ends in zero. 11 Estimate the following products using 1 figure approximations: a 49 £ 32 b 83 £ 57 c 58 £ 43 e 519 £ 38 f 88 £ 307 g 728 £ 65 i 58 975 £ 8 j 31 942 £ 6 k 6412 £ 37 d h l 389 £ 21 921 £ 78 29 £ 7142 cyan Y:\HAESE\SA_06\SA06_01\029SA601.CDR Mon Aug 25 09:19:53 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 If two factors in a product are both “halfway” numbers, a closer approximation is obtained by rounding the smaller number up and the larger number down. black SA_06 Color profile: Disabled Composite Default screen 30 WHOLE NUMBERS (CHAPTER 1) Example 18 By rounding each number off to 1 digit, estimate the following: a 45 £ 35 b 650 £ 25 a If both are rounded up: 45 £ 35 is approximately 50 £ 40 fRound up for 5g which is approximately 2000 The correct answer is 1575. Notice that 45 £ 35 is approximately 40 £ 40 fBoth end in 5 so which is approximately 1600 round one up and which is closer to 1575 than 2000. the other downg ) a closer approximation is found by rounding the smaller one up and the larger one down. fBoth end in 5 so round one up and the other downg 650 £ 25 is approximately 600 £ 30 which is approximately 18 000 b 12 Estimate the products a 45 £ 15 d 550 £ 35 g 950 £ 45 65 £ 25 95 £ 95 9500 £ 45 b e h 75 £ 85 750 £ 15 2500 £ 85 c f i Find the difference in the estimates in f and h, when both factors are rounded up, and when one is rounded up and the other rounded down. Example 19 Find the approximate value of the quotient of 5968 ¥ 51 4 20 5 5968 ¥ 51 is approximately 6000 ¥ 50 which is approximately 600 ¥ 5 which is approximately 120 quotient dividend divisor 79 £ 196 16 684 15 484 160 484 f 3945 £ 32 120 400 12 040 126 240 g 8151 ¥ 19 3209 429 329 cyan Y:\...\SA_06-2\SA06_01\030SA601.CDR Fri Sep 19 17:28:03 2003 magenta yellow 95 e 100 299 50 209 75 2999 25 897 ¥ 3 0 d 5 4392 95 43 920 100 49 320 50 685 £ 72 75 c 25 2604 0 26 404 5 2804 95 93 £ 28 100 b 50 11 344 75 14310 25 1134 0 126 £ 9 5 95 a 100 50 75 25 0 5 13 Use estimation to find which of these calculator answers is reasonable: black When multiplying, the total number of digits in the questions often shows how many digits will be in the answer. SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) 31 14 In the following questions, round the given data to one figure to find the approximate value asked for: a A large supermarket has 12 rows of cars in its carpark. If each row has approximately 50 cars, estimate the total number of cars in the park. b A school canteen has 11 shelves in its fridge. Estimate the number of drinks in the fridge if there are approximately 21 drinks on each shelf. c Scott reads 19 pages in one hour. At this rate, estimate how long it will take him to read a 413 page novel. d Each student is expected to raise approximately $28 in a school’s spellathon. If 397 students take part, estimate the amount the school could expect to raise. e A school trip needs one adult helper for every 5 students. Approximately how many adults are needed if 95 students are going on the trip? f Estimate the number of students in a school if there are 21 classes with approximately 28 students in each class. Example 20 Estimate the number of paper clips on the sheet of paper: 1 Divide the paper into equal parts as shown: 2 Count the number of paper clips in one part. 3 Multiply the paper clips in one part by the total number of parts. cyan Y:\...\SA_06-2\SA06_01\031SA601.CDR Wed Sep 17 16:36:17 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 Number of paper clips in 1 part £ number of parts = 7 £ 8 = 56 paper clips Estimate: 56 paper clips are lying on the sheet of paper. black SA_06 Color profile: Disabled Composite Default screen 32 WHOLE NUMBERS (CHAPTER 1) 15 Using the method outlined in Example 20, estimate the number in each of the following: a Buttons b Arrows Words c d Spheres f Gears presently; but towards noon the raft had been found lodged against the Missouri shore some five or six miles below the village and then hope perished; they must be drowned else hunger would have driven them home by nightfall if not sooner It was believed that the search for the bodies had been a fruitless effort merely because the drowning must have occurred in mid-channel since the boys being good swimmer would otherwise hive escaped to shore This was Wednesday night If the bodies contemned missing until Sunday all hope would be given over; and the funerals would be preached on that morning Tom shuddered Mrs Harare gave a sobbing goodnight and turned to go Then with a mutual impulse the two bereaved women flung themselves into each other’s arms and had a good consoling cry and then parted Aunt Pole was tender far beyond her wont in her goodnight to Sid and Mary Sid snuffed a bit and Mary went off crying with all her heart Aunt Pole knelt down and prayed for Tom so touchingly so kingly and with such measureless love in her words and her trembling that he was weltering in tea again long she was through He had to keep still long after she went to bed for she kept making broken-hearted from time to time tossing and turning over But at last she was still only moaning a little in her sleep Now the boy stole out rose gradually by the bedside shaded the candlelight with his hand and stood regarding her His heart was full of pity for her He took out his sycamore scroll and placed it by the candle But something occurred to him and he lingered considering His face lighted with a happy solution of his thought; he put the bark hastily in his pocket then he bent over and kissed the faded lips and straightway made his stealthy exit latching the door behind him He threaded his way back to the ferry landing found nobody at large there and walked boldly on board the boat for he knew she was tenantless except that there was a watch man who always turned in and sae t like a graven image He untied the skiffat the stern slip Into it and was soon rowing cautiously up 8 stream When he had pulled a the village started quartering across and bent himself stoutly to his work He hit the landing on the other side neatly for this was a familiar bit of work to him He was moved to capture the skiffarguing that’ it I might be considered e Tiles DEMO PRINTABLE TEMPLATE H PLACE VALUE Over the next few pages there are a number of activities designed to help you understand place value. An understanding of values up to the hundred thousand place will make the understanding of very large whole numbers and very small decimal numbers much easier to understand. Multi Attribute blocks (MA blocks) are one practical way of showing the value in a base 10 system. cyan Y:\...\SA_06-2\SA06_01\032SA601.CDR Mon Sep 29 12:20:24 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 This diagram of MA blocks represents the number three thousand five hundred and forty nine (3549): black SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) In some older number systems, the order in which the symbols were written did not change the value of the number. However, in the HinduArabic system the order of the digits and the place in which they are put is very important. 33 The place or a position of a digit in a number determines its value. Consider what would happen in the above example if the digits 3 and 9 changed positions. The PV blocks would need to be changed as below: The value of the 9 which represented 9 units has now changed to represent 9 thousand. Each time a digit moves one place to the left its value increases ten times. Conversely, each time a digit moves one place to the right its value decreases ten times. EXERCISE 1H 1 What number is represented by the following? a b 2 Draw representations of the following: a 3094 b 4186 ACTIVITY NOTATION CARDS What to do: 1 cm 1 To make a notation card draw up a piece of card like the one given. Name all the places but leave off the numbers. 1 cm Thousands Hundreds Tens yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 Y:\HAESE\SA_06\SA06_01\033SA601.CDR Fri Aug 29 16:27:30 2003 magenta Units Hundreds Tens Units 2 cm 6 cm cyan Units black 6 cm SA_06 Color profile: Disabled Composite Default screen 34 WHOLE NUMBERS (CHAPTER 1) 2 Cut up another piece of card into ten 4-square-cm squares and write the digits from 0 to 9 on one side. Shuffle the squares then write the numbers 0 to 9 on the other side of the squares. This gives you 2 lots of digits from 0 to 9. 3 Place the digits at random on the Notation Card. Practice saying the numbers by starting from the left and reading the numbers in groups of three. 2 cm 2 cm Thousands Hundreds Tens Units Units Hundreds Tens Units 4 1 9 2 5 7 For example, group the number given like this: 419 (thousand group) 257 (unit group). Grouping or chunking a small number of digits makes them easier to say. We often “group” phone numbers. EXERCISE 1H (continued) 3 Write in numerals and words the a largest make with the digits 0 to 9 (not repeated). b smallest six digit number you can 4 In numerals and words, what is the difference between the largest and smallest number in 3? 5 What is the sum of the largest and smallest numbers in 3? cyan Y:\HAESE\SA_06\SA06_01\034SA601.CDR Mon Sep 01 12:55:20 2003 magenta yellow 95 100 50 75 25 0 Ascending means going up. 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 6 Starting with the smallest number that can be made with all the digits 0 to 3 using them once only, list in ascending order all the numbers that can be formed. black SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) Ten thousands Thousands Hundreds Tens Units ten thousand cents one thousand cents one hundred cents ten cents one cent two thousand cents two hundred cents twenty cents two cents five thousand cents five hundred cents fifty cents five cents 35 On the chart above, if one cent represents the unit, then ten cents represents the tens, a dollar represents the hundreds, ten dollars represents the thousands and one hundred dollars represents the ten thousands place. cyan Y:\...\SA_06-2\SA06_01\035SA601.CDR Wed Sep 10 09:19:50 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 f 5 e 95 d 100 c 50 b 75 a 25 0 5 95 100 50 75 25 0 5 7 Write the place values for the sum of the following amounts: black SA_06 Color profile: Disabled Composite Default screen 36 WHOLE NUMBERS (CHAPTER 1) 8 What would be the monetary values of a 8765 cents b 24 075 cents d fifteen thousand four hundred and forty cents e ninety eight thousand three hundred and seven cents f the sum of all the money 7 a , b and c ? 56 908 cents c 9 In the place-value card game for the highest number, which hand of each pair of hands “wins”? 6 ªª ªªª ªª 6 9 § § § § § § 6 8 9 A 9 A 6 6 i sum of In words, write the B 7 ªª ªª ªª 9 § § § § §§§ § § § § § § § § § § § A 9 9 7 6 8 9 7 2 § § § § § § § 9 7 7 ªª ªªª ªª A 9 9ª ª B A 4 6 § § § § §§§ § § § § § § § 7 9 7 7 5 7 7 8 §§§ § § § § 9 9 6 § 8 A A 2 c ª 9§ § 4 5 A ªª ª ªª 4 A B 5 ª 9 b 2 8 ªª ªªª ªª 8 9ª ª 4 5 A 2 a ii difference between each pair of hands Find the sum of each column (A and B). 10 Using the abacus VIDEO DEMO In this simple abacus each column represents a place value. Using whole numbers, the unit is the far right column. The beads in the first example represent 251¡463 which we say as 251 thousand 463. What numbers do the beads in a and b represent? a b ACTIVITY CARDS AND PLACE VALUE What to do: yellow 95 100 50 75 25 0 5 95 100 50 75 Ten Hundred Thousands Hundreds thousands thousands 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 6 0 A 9 5 7 4 8 7 Y:\...\SA_06-2\SA06_01\036SA601.CDR Wed Sep 17 13:50:59 2003 magenta 9 4 cyan 6 black Tens 8 This is a card game for 2 to 6 players. Each player has a place value chart in which each space is large enough to comfortably place a standard sized playing card. The chart should have the place value names written on it. Units SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) 37 From a full pack, remove all the picture cards and the 10’s, leaving the aces as ones. There are thirty six cards from ones to nines. The cards are then shuffled and placed face down in a pack. Taking it in turns each player must first nominate the place-value of the card they are about to pick up from the pack. In the example above, the player first nominated the ten thousand space and then picked up a 9. The same player’s second turn was to nominate the hundreds place and she picked up an ace. Her third pick was for the hundred thousand place and she picked up a 6. Each turn she had to nominate a place value that she had not used before she picked up a card. In this example she finished the game with 697 148. You could play this game to see who could get either the highest or lowest possible number with the six cards chosen. EXERCISE 1H (continued) 11 Using a calculator, key in the numbers as shown: a Now subtract 5678. Say the number and write down the digit which appears in the thousands place. Repeat this subtraction process 5 more times, that is, say the number and write the digit. b What number is left after you have subtracted 6 times? c What is the highest number you can make with the digits you have written? d What is the lowest number you can make with the digits you have written? e In the highest number, what digit appears in the thousands place? cyan Y:\HAESE\SA_06\SA06_01\037SA601.CDR Fri Aug 29 16:28:08 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 a Key in the number 23, then multiply it by 3 and write down your answer. Multiply your new answer by 3, say the number then write it down. Keep on repeating this pattern until you have a 4 digit in the hundred thousands place. b How many times did you multiply by 3? c What is the number? d In your answers, how many times did the 7 digit appear in the hundreds place? 25 0 5 95 100 50 75 25 0 5 12 123609 black SA_06 Color profile: Disabled Composite Default screen 38 WHOLE NUMBERS (CHAPTER 1) I NUMBER LINE A line on which equally spaced points are marked is called a number line. 7 8 9 10 11 12 13 7 8 not a number line 9 10 11 12 13 correct number line A number line allows the order and relative positions of numbers to be shown. 21 26 23 22 25 24 27 120 130 140 150 160 170 180 order and positions not relative order and relative positions The arrow head shows that the line can continue indefinitely. Many number lines like rulers, tape measures, scales and speedometers have positive integers. They start from zero. F 0 1 2 3 4 5 6 E 7 8 9 10 60 FUEL 11 12 40 20 13 14 80 100 120 140 160 KM/H 180 0 15 200 16 Some number lines like weather and fridge thermometers and devices for measuring depth in submarines and charges in batteries, have positive and negative integers. This example shows a graph of the set of numbers 3, 6, 9 and 15. Example 21 Show the numbers 9, 15, 3 and 6 with dots on a number line. We rearrange 9, 15, 3 and 6 in ascending order i.e., 3, 6, 9, 15: 15 ¡ 3 = 12 fcalculate the range of equal spaces needed, highest to lowestg cyan Y:\...\SA_06-2\SA06_01\038SA601.CDR Wed Sep 17 16:47:00 2003 magenta yellow 95 100 20 50 0 5 95 15 100 50 75 25 0 5 95 15 10 100 50 75 25 0 5 5 95 100 50 75 25 0 5 0 9 75 6 25 3 black SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) 39 Number lines can also be used to show the four basic operations of adding, subtracting, multiplying and dividing, with number. Example 22 DEMO Perform the following operations on a number line: a b 4£3+2 3+8¡6 3+8¡6 =5 a 4 £ 3 + 2 = 14 b c 0 5 10 15 0 5 10 15 23 ¥ 5 Choose a suitable scale f¥ is opposite of £g c 0 3 23 ¥ 5 10 ) start from right side. 15 20 25 23 ¥ 5 = 4 with a remainder of 3. EXERCISE 1I 1 Use a b c d e f dots to show the following numbers on a number line: 9, 4, 8, 2, 7 14, 19, 16, 18, 13 70, 30, 60, 90, 40 multiples of 4 below 40 250, 75, 200, 25, 125 4000, 3000, 500, 2500, 1500 2 What operations do the following number lines show? Give a final answer. a b 0 5 10 15 20 0 c 5 10 15 20 d 0 10 20 30 40 50 0 e 100 200 300 400 500 600 700 f 0 10 20 30 40 50 60 70 0 5 10 15 20 cyan Y:\...\SA_06-2\SA06_01\039SA601.CDR Fri Sep 19 17:29:33 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 3 Draw a number line and show the following operations. Give a final answer. a 9+8¡6 b 2+4+8¡2 c 40 + 70 + 90 ¡ 50 d 55 + 60 + 75 ¡ 40 e 3£9¡8 f 4£6¥5 black SA_06 Color profile: Disabled Composite Default screen 40 WHOLE NUMBERS (CHAPTER 1) Number lines can also show order and relative positions for fractions. For example 0 Qt_ Wt_ Et_ Rt_ 1 1\Qt_ 1\Wt_ 1\Et_ 1\Rt_ 2 2.5 2.6 2\Qt_ and decimals 1.7 1.8 1.9 J 2.0 2.1 2.2 2.3 2.4 2.7 NUMBER PUZZLES (EXTENSION) EXERCISE 1J 1 In the eleven squares write all the numbers from 1 to 11 so that every set of three numbers in a straight line adds up to 18. 2 Draw three triangles like the one shown. Using each number once only, place the numbers 2 to 7 in the squares so that each side of the triangle adds up to 12 a b 13 c 14 3 Draw three triangles like the one shown. Using each number once only, place the numbers 11 to 19 in the triangles so that each side of the triangle adds up to a 57 b 59 c 63 4 Draw three shapes as shown. Using each number once only, place the numbers 1 to 10 in the circles so that each line leading to the centre adds up to 19 a b 21 c 25 cyan Y:\HAESE\SA_06\SA06_01\040SA601.CDR Mon Aug 25 11:15:31 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 PRINTABLE TEMPLATE black SA_06 Color profile: Disabled Composite Default screen WHOLE NUMBERS (CHAPTER 1) 41 PRINTABLE TEMPLATE 5 Copy the grid below and then complete these cross numbers. There is only one way in which all the numbers will fit. 2 digits eighty six, ninety, twenty five, seventy eight, forty five, forty one, seventy five, forty two, forty three, seventy two, eighty five 6 3 digits 739, 246, 208, 267, 846, 540 4 digits 9306, 9346, 4098, 8914, 2672, 1984, 2635, 8961 5 digits fifty six thousand three hundred and eighty four, 53 804, forty four thousand nine hundred and sixty seven, 36 495. REVIEW SET A CHAPTER 1 1 Give the numbers represented by the Roman symbols: a 23 2 Write the following numbers in Roman symbols: 3 Give the number represented by the digit 2 in a VIII a 253 b LIV b 110 b 12 467 4 Express 3 £ 10 000 + 4 £ 100 + 5 £ 10 + 9 in simplest form. 5 Write the smallest whole number you can make with the digits 6, 3, 1, 1, 2. 6 Write fifty three thousand and seventy two in numerical form. 7 Write the operations and answer in numerical form: three hundred and six more than four thousand and eleven. 8 Round the following: a 64 762 to the nearest 10 000 c $1:98 to the nearest 5 cents b 1976 grams to the nearest kilogram 9 Estimate the cost of 31 calculators at $37:85 each. 10 Estimate the difference between 2061 and 477. 11 Write $1620 as cents. 12 Show the first six even numbers as dots on a number line. 13 What operations does the number line show? Give a final answer. 0 5 10 15 REVIEW SET B CHAPTER 1 Y:\HAESE\SA_06\SA06_01\041SA601.CDR Mon Aug 25 11:16:12 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 1 Give the numbers represented by the Greek symbols: cyan 20 black a b SA_06 Color profile: Disabled Composite Default screen 42 WHOLE NUMBERS (CHAPTER 1) a 23 2 Write the following numbers in Greek symbols: 3 Give the number represented by the digit 6 in b 1000 a 45 362 b 63 549 4 Express 5 £ 10 000 + 2 £ 1000 + 3 £ 10 + 7 in simplest form. 5 Write 2469 in expanded form. 6 Write the numeral 51 602 in words. 7 Write the operations and answer in numerical form: twenty seven less than two thousand and three. 8 Round the following: a 52 794 to the nearest 1000 c $4:92 to the nearest 5 cents b 375 cm to the nearest metre 9 Estimate the sum of 69 753 and 4690. 10 Estimate the product of 671 and 49 using 1 figure approximations. 11 Write 6005 cents as dollars. 12 Show the multiples of 3 less than 20 as dots on a number line. 13 Show the operations 4 £ 3 ¡ 8 on a number line. Give a final answer. REVIEW SET C CHAPTER 1 1 Give the numbers represented by the Roman symbols: a XIX a 11 2 Write the following numbers using Roman symbols: b XXXV b 43 3 Give the number represented by the digit 9 in 59 632. 4 Express 9 £ 10 000 + 5 £ 1000 + 4 £ 100 + 6 in simplest form. a Write the largest whole number possible with the digits 0, 2, 3, 7, 9. b Write 37 029 in expanded form. 5 6 Write fifty thousand six hundred and ten in numerical form. 7 Write the operations and answer in numerical form: increase 863 by 794. 8 Round the following: a 5607 to the nearest 10 b 9 Estimate the following: a 6493 + 2172 ¡ 3698 $634:27 to the nearest 5 cents 450 £ 65 b c 23 £ $49:20 10 Show the first three multiples of 5 on a number line. 11 What operations does the number line show? Give a final answer. 0 5 10 15 20 cyan Y:\HAESE\SA_06\SA06_01\042SA601.CDR Tue Aug 26 11:59:27 2003 magenta yellow 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 95 100 50 75 25 0 5 12 Show the operations 5 + 5 £ 2 on a number line. Give a final answer. black SA_06
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