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More Than Just a Textbook
For StudentsConnect to StudentWorks Plus Online which contains all of the following online assets. You don’t need to take your textbook home every night.
• Personal Tutor• Chapter Readiness Quizzes• Multilingual eGlossary
• Concepts in Motion• Chapter Test Practice• Test Practice
For TeachersConnect to professional development content at glencoe.com and eBook Advance Tracker at AdvanceTracker.com
For ParentsConnect to glencoe.com for access to StudentWorks Plus Online and all the resources for students and teachers that are listed above.
Internet ResourcesStep 1 Connect to Math Online glencoe.com
Step 2 Connect to online resources by using codes. You can connect directly to the chapter you want.
IM7048c1Enter this code with
the appropriate chapter number.
The algebra content for IMPACT Mathematics was adapted from the series Access to Algebra, by Neville Grace, Jayne Johnston, Barry Kissane, Ian Lowe, and Sue Willis. Permission to adapt this material was obtained from the publisher, Curriculum Corporation of Level 5, 2 Lonsdale Street, Melbourne, Australia.
Copyright © 2009 by The McGraw-Hill Companies, Inc. All rights reserved. Permission is granted to reproduce the material contained herein on the condition that such materials be reproduced only for classroom use; be provided to students, teachers, and families without charge; and be used solely in conjunction with the Glencoe/McGraw-Hill IMPACT Mathematics program. Any other reproduction, for sale or other use, is expressly prohibited.
Send all inquiries to:Glencoe/McGraw-Hill8787 Orion PlaceColumbus, OH 43240-4027
ISBN: 978-0-07-888704-8MHID: 0-07-888704-6
Printed in the United States of America.
1 2 3 4 5 6 7 8 9 10 055/079 17 16 15 14 13 12 11 10 09 08
These materials include work supported in part by the National Science Foundation under Grant No. ESI-9726403 to MARS (Mathematics Assessment Resource Service). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the funding agencies. For more information on MARS, visit http://www.nottingham.ac.uk/education/MARS.
About the Cover
Hammers can be used to drive nails. They can also be used to shape metal that is struck against an anvil.
In ancient times, the renowned Greek mathematician Pythagoras noticed the exceptional sounds of hammers striking anvils. He determined that the weights of different-sized hammers were proportional, with weights of 12, 9, 8, and 6 pounds. Upon further examination, he determined that the harmonious sounds were a result of the numerical relationships among the hammers’ weights and discovered a connection among numbers, ratios, and music.
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1010
G7-FP3
G7-FP3
G7-FP3
G7-FP3
G7-FP2, G7-FP4C
G7-FP6C, G7-FP7C
G7-FP3, G7-FP5C
G7-FP1, G7-FP3,
G7-FP5C
G7-FP3, G7-FP5C
G7-FP1, G7-FP4C
Expressions ............................................................................................ 2
Exponents ............................................................................................ 72
Signed Numbers ....................................................................... 124
Magnitude of Numbers ................................................... 172
Geometry in Three Dimensions ............................ 210
Data and Probability .......................................................... 260
Real Numbers .............................................................................. 318
Linear Relationships .......................................................... 366
Equations ............................................................................................434
Proportional Reasoning and Percents ........ 492
Contents in Briefand ConnectionsSee pages vi and vii for key.
iii
Principal InvestigatorFaye Nisonoff RuoppBrandeis UniversityWaltham, Massachusetts
Consultants and DevelopersConsultants
Frances Basich WhitneyProject Director, Mathematics K–12Santa Cruz County Office of EducationSanta Cruz, California
Dr. Selina Vásquez MirelesAssociate Professor of MathematicsTexas State University—San MarcosSan Marcos, Texas
Robyn SilbeyMathematics Content CoachMontgomery County Public SchoolsGaithersburg, Maryland
Teri WillardAssistant ProfessorCentral Washington UniversityEllensburg, Washington
Special thanks to:Peter BraunfeldProfessor of Mathematics EmeritusUniversity of Illinois
Sherry L. MeierAssistant Professor of MathematicsIllinois State University
Judith RoitmanProfessor of Mathematics University of Kansas
DevelopersSenior Project DirectorCynthia J. Orrell
Senior Curriculum DevelopersMichele Manes, Sydney Foster, Daniel Lynn Watt, Ricky Carter, Joan Lukas, Kristen Herbert
Curriculum DevelopersHaim Eshach, Phil Lewis, Melanie Palma, Peter Braunfeld, Amy Gluckman, Paula Pace
Special ContributorsElizabeth D. Bjork, E. Paul Goldenberg
iv
Project ReviewersGlencoe and Education Development Center would like to thank the curriculum specialists, teachers, and schools who participated in the review and testing of the first edition of IMPACT Mathematics. The results of their efforts were the foundation for this second edition. In addition, we appreciate all of the feedback from the curriculum specialists and teachers who participated in review and testing of this edition.
Debra AllredMath TeacherWiley Middle SchoolLeander, Texas
Tricia S. BiesmannRetired TeacherSisters Middle SchoolSisters, Oregon
Kathryn Blizzard BallinSecondary Math SupervisorNewark Public SchoolsNewark, New Jersey
Linda A. BohnyDistrict Supervisor of MathematicsMahwah Township School DistrictMahwah, New Jersey
Julia A. ButlerTeacher of MathematicsRichfield Public School AcademyFlint, Michigan
April ChauvetteSecondary Mathematics FacilitatorLeander ISDLeander, Texas
Amy L. ChazarettaMath Teacher/Math Department ChairWayside Middle School, EM-S ISDFort Worth, Texas
Franco A. DiPasquaDirector of K–12 MathematicsWest Seneca CentralWest Seneca, New York
Mark J. ForzleyJunior High School Math TeacherWestmont Junior High SchoolWestmont, Illinois
Virginia G. HarrellEducation ConsultantBrandon, Florida
Lynn HurtDirectorWayne County SchoolsWayne, West Virginia
Andrea D. Kent7th Grade Math & Pre-AlgebraDodge Middle School, TUSDTucson, Arizona
Russ Lush6th Grade Teacher & Math Dept. ChairNew Augusta—NorthIndianapolis, Indiana
Katherine V. Martinez De MarchenaDirector of Education 7–12Bloomfield Public SchoolsBloomfield, New Jersey
Marcy MyersMath FacilitatorSouthwest Middle SchoolCharlotte, North Carolina
Joyce B. McClainMiddle School Mathematics ConsultantHillsborough County SchoolsTampa, Florida
Suzanne D. ObuchowskiMath TeacherProctor SchoolTopsfield, Massachusetts
Michele K. OlderMathematics InstructorEdward A. Fulton Jr. HighO’Fallon, Illinois
Jill PlattnerMath Program Developer (Retired)Bend La Pine School DistrictBend, Oregon
E. Elaine RaffertyRetired Math CoordinatorSummerville, South Carolina
Karen L. ReedMath Teacher—Pre-APChisholm Trail IntermediateFort Worth, Texas
Robyn L. RiceMath Department ChairMaricopa Wells Middle SchoolMaricopa, Arizona
Brian StilesMath TeacherGlen Crest Middle SchoolGlen Ellyn, Illinois
Nimisha Tejani, M.Ed.Mathematics TeacherKino Jr. HighMesa, Arizona
Stefanie TurnageMiddle School MathematicsGrand Blanc AcademyGrand Blanc, Michigan
Kimberly WaltersMath TeacherCollinsville Middle SchoolCollinsville, Illinois
Susan WessonMath Teacher/ConsultantPilot Butte Middle SchoolBend, Oregon
Tonya Lynnae WilliamsTeacherEdison Preparatory SchoolTulsa, Oklahoma
Kim C. WrightenberryMath TeacherCane Creek Middle SchoolAsheville, North Carolina
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The Curriculum Focal Points identify key mathematical ideas for this grade. They are not discrete topics or a checklist to be mastered; rather, they provide a framework for the majority of instruction at a particular grade level and the foundation for future mathematics study. The complete document may be viewed at www.nctm.org/focalpoints.
G7-FP1 Number and Operations and Algebra and Geometry: Developing an understanding of and applying proportionality, including similarityStudents extend their work with ratios to develop an understanding of proportionality that they apply to solve single and multistep problems in numerous contexts. They use ratio and proportionality to solve a wide variety of percent problems, including problems involving discounts, interest, taxes, tips, and percent increase or decrease. They also solve problems about similar objects (including figures) by using scale factors that relate corresponding lengths of the objects or by using the fact that relationships of lengths within an object are preserved in similar objects. Students graph proportional relationships and identify the unit rate as the slope of the related line. They distinguish proportional relationships (
y _ x = k, or y = kx) from other
relationships, including inverse proportionality (xy = k, or y = k _ x ).
G7-FP2 Measurement and Geometry and Algebra: Developing an understanding of and using formulas to determine surface areas and volumes of three-dimensional shapesBy decomposing two- and three-dimensional shapes into smaller, component shapes, students find surface areas and develop and justify formulas for the surface areas and volumes of prisms and cylinders. As students decompose prisms and cylinders by slicing them, they develop and understand formulas for their volumes (Volume = Area of base × Height). They apply these formulas in problem solving to determine volumes of prisms and cylinders. Students see that the formula for the area of a circle is plausible by decomposing a circle into a number of wedges and rearranging them into a shape that approximates a parallelogram. They select appropriate two- and three dimensional shapes to model real-world situations and solve a variety of problems (including multistep problems) involving surface areas, areas and circumferences of circles, and volumes of prisms and cylinders.
G7-FP3 Number and Operations and Algebra: Developing an understanding of operations on all rational numbers and solving linear equationsStudents extend understandings of addition, subtraction, multiplication, and division, together with their properties, to all rational numbers, including negative integers. By applying properties of arithmetic and considering negative numbers in everyday contexts (e.g., situations of owing money or measuring elevations above and below sea level), students explain why the rules for adding, subtracting, multiplying, and dividing with negative numbers make sense. They use the arithmetic of rational numbers as they formulate and solve linear equations in one variable and use these equations to solve problems. Students make strategic choices of procedures to solve linear equations in one variable and implement them efficiently, understanding that when they use the properties of equality to express an equation in a new way, solutions that they obtain for the new equation also solve the original equation.
KEYG7-FP1
Grade 7 Focal Point 1
G7-FP2 Grade 7 Focal Point 2
G7-FP3 Grade 7 Focal Point 3
G7-FP4C Grade 7 Focal Point 4
Connection
G7-FP5C Grade 7 Focal Point 5
Connection
G7-FP6C Grade 7 Focal Point 6
Connection
G7-FP7C Grade 7 Focal Point 7
Connection
vi
Connections to the Focal Points
G7-FP4C Measurement and Geometry: Students connect their work on proportionality with their work on area and volume by investigating similar objects. They understand that if a scale factor describes how corresponding lengths in two similar objects are related, then the square of the scale factor describes how corresponding areas are related, and the cube of the scale factor describes how corresponding volumes are related. Students apply their work on proportionality to measurement in different contexts, including converting among different units of measurement to solve problems involving rates such as motion at a constant speed. They also apply proportionality when they work with the circumference, radius, and diameter of a circle; when they find the area of a sector of a circle; and when they make scale drawings.
G7-FP5C Number and Operations: In grade 4, students used equivalent fractions to determine the decimal representations of fractions that they could represent with terminating decimals. Students now use division to express any fraction as a decimal, including fractions that they must represent with infinite decimals. They find this method useful when working with proportions, especially those involving percents. Students connect their work with dividing fractions to solving equations of the form ax = b, where a and b are fractions. Students continue to develop their understanding of multiplication and division and the structure of numbers by determining if a counting number greater than 1 is a prime, and if it is not, by factoring it into a product of primes.
G7-FP6C Data Analysis: Students use proportions to make estimates relating to a population on the basis of a sample. They apply percentages to make and interpret histograms and circle graphs.
G7-FP7C Probability: Students understand that when all outcomes of an experiment are equally likely, the theoretical probability of an event is the fraction of outcomes in which the event occurs. Students use theoretical probability and proportions to make approximate predictions.
Reprinted with permission from Curriculum Focal Points for Prekindergarten through Grade 8 Mathematics: A Quest for Coherence, copyright 2006, by the National Council of Teachers of Mathematics. All rights reserved.
vii
Table of ContentsExpressions ............................................................................. 2Lesson 1.1 Variables and Expressions ........................ 4 Investigation 1: Sequences and Rules ........................................ 5
Investigation 2: Write Expressions ............................................... 9
Investigation 3: Evaluate Expressions ........................................12
Investigation 4: Flowcharts ..........................................................17
On Your Own Exercises .............................................................21
Lesson 1.2 Expressions and Formulas ..................... 30 Investigation 1: What’s the Variable? ........................................ 32
Investigation 2: Formulas ............................................................ 35
Inquiry Investigation 3: Formulas and Spreadsheets ..... 40
On Your Own Exercises ............................................................ 43
Lesson 1.3 The Distributive Property ........................ 49 Investigation 1: Bags and Blocks ............................................... 51
Investigation 2: The Same and Different ................................. 53
Investigation 3: Use Parentheses .............................................. 56
Investigation 4: Combine Like Terms ....................................... 60
On Your Own Exercises ............................................................ 63
Review & Self-Assessment ...................................................... 69
▼▼
1
G7-FP3
and ConnectionsSee pages vi and vii for key.
viii
Exponents ................................................................................. 72Lesson 2.1 Factors and Multiples .................................. 74 Investigation 1: Factors ....................................................................75
Investigation 2: Prime Numbers .................................................. 77
Investigation 3: Common Factors ................................................ 80
Investigation 4: Multiples .............................................................. 83
On Your Own Exercises ............................................................... 86
Lesson 2.2 Exponent Machines ...................................... 92 Investigation 1: Model Exponents ............................................... 93
Investigation 2: Multiply Expressions with the Same Base ..... 96
Investigation 3: Multiply Expressions with the Same Exponent ................................................ 100
On Your Own Exercises ................................................................. 104
Lesson 2.3 More Exponent Machines ..................... 107 Investigation 1: Division Machines with Exponents .............. 107
Investigation 2: Divide Expressions with Exponents .............. 109
Investigation 3: Power Law of Exponents ............................... 111
Inquiry Investigation 4: The Tower of Hanoi ...................... 114
On Your Own Exercises ............................................................ 117
Review & Self-Assessment ..................................................... 120
▼▼
2
G7-FP3
and ConnectionsSee pages vi and vii for key.
ix
3 Signed Numbers ............................................................ 124Lesson 3.1 Add and Subtract with Negative
Numbers ............................................................. 126 Investigation 1: The Two-Color Chip Model ............................. 128
Inquiry Investigation 2: A Number Line Model .................. 131
Investigation 3: Add and Subtract on the Number Line ........ 134
Investigation 4: Equivalent Operations ...................................... 140
Investigation 5: Inequalities and Negative Numbers .............. 143
Investigation 6: Predict Signs of Sums and Differences ........ 146
On Your Own Exercises ............................................................. 148
Lesson 3.2 Multiply and Divide with Negative Numbers ............................................................. 154
Investigation 1: Multiply a Positive and a Negative ................ 155
Investigation 2: Multiply Two Negatives ....................................157
Investigation 3: Divide with Negative Numbers ...................... 160
Investigation 4: Signed Numbers and Data .............................. 162
On Your Own Exercises ............................................................. 165
Review & Self-Assessment ...................................................... 169
▼▼
G7-FP3
and ConnectionsSee pages vi and vii for key.
x
4 Magnitude of Numbers ...................................... 172Lesson 4.1 Scientific Notation ........................................ 174 Investigation 1: Powers of 10 ..................................................... 175
Investigation 2: Work with Scientific Notation ......................... 178
Investigation 3: Scientific Notation on a Calculator ................ 182
Inquiry Investigation 4: Relative Error ................................... 185
On Your Own Exercises ............................................................. 188
Lesson 4.2 Negative Exponents .................................... 194 Investigation 1: Model Negative Exponents ............................. 194
Investigation 2: Evaluate Expressions with Negative Exponents ........................................................... 198
Investigation 3: Laws of Exponents and Scientific Notation .............................................................. 200
On Your Own Exercises ............................................................. 202
Review & Self-Assessment ...................................................... 207
▼▼G7-FP3
and ConnectionsSee pages vi and vii for key.
xi
5 Geometry in Three Dimensions ............. 210Lesson 5.1 Surface Area and Volume ...................... 212 Investigation 1: Measure Prisms ................................................. 213
Investigation 2: Volume of Prisms and Cylinders ................... 216
Inquiry Investigation 3: Package Design .............................. 220
On Your Own Exercises ............................................................. 223
Lesson 5.2 Nets and Solids .............................................. 228 Investigation 1: Use a Net ........................................................... 229
Investigation 2: Use Nets to Investigate Solids ........................ 230
Investigation 3: Is Today’s Beverage Can the Best Shape? ... 233
On Your Own Exercises ............................................................. 235
Lesson 5.3 Mass and Weight .......................................... 240 Investigation 1: Measure Mass .................................................... 241
Investigation 2: Estimate Mass .................................................... 244
Investigation 3: Measure Weight ................................................ 247
On Your Own Exercises ............................................................. 251
Review & Self-Assessment ...................................................... 256
▼▼
G7-FP2
G7-FP4C
and ConnectionsSee pages vi and vii for key.
xii
6 Data and Probability .............................................. 260Lesson 6.1 Dependence .................................................... 262 Investigation 1: Combinations and Probability ........................ 262
Investigation 2: Heads or Tails? .................................................. 264
Investigation 3: Is It Fair? ............................................................. 268
Inquiry Investigation 4: The Hidden Prize ............................ 270
On Your Own Exercises ............................................................. 272
Lesson 6.2 Make Predictions .......................................... 278 Investigation 1: Samples and Predictions ................................. 279
Investigation 2: Sample Sizes ...................................................... 280
Investigation 3: Representative Samples .................................. 283
On Your Own Exercises ............................................................. 286
Lesson 6.3 Data Graphs ..................................................... 294 Investigation 1: Double Bar and Double Line Graphs ........... 295
Investigation 2: Make a Circle Graph ......................................... 299
Investigation 3: Stem-and-Leaf Plots ......................................... 302
Investigation 4: Misleading Statistics and Graphs ................... 306
On Your Own Exercises ............................................................. 309
Review & Self-Assessment ...................................................... 314
▼▼G7-FP6C
G7-FP7C
and ConnectionsSee pages vi and vii for key.
xiii
7 Real Numbers ................................................................... 318Lesson 7.1 Rational Numbers ........................................ 320 Investigation 1: Number Sets ...................................................... 320
Investigation 2: Order and Compare Rational Numbers ....... 324
On Your Own Exercises ............................................................. 328
Lesson 7.2 Irrational Numbers ...................................... 331 Investigation 1: Squares and Square Roots ............................. 331
Investigation 2: Approximate Irrational Numbers ................... 336
On Your Own Exercises ............................................................. 339
Lesson 7.3 The Pythagorean Theorem .................... 343 Investigation 1: Right Triangles and Squares ........................... 343
Investigation 2: Use the Pythagorean Theorem ...................... 347
Inquiry Investigation 3: The Distance Formula ................... 351
On Your Own Exercises ............................................................. 355
Review & Self-Assessment ...................................................... 361
▼▼
G7-FP3
G7-FP5C
and ConnectionsSee pages vi and vii for key.
xiv
8 Linear Relationships .............................................. 366Lesson 8.1 Rates ...................................................................... 368 Investigation 1: Understand Rates ............................................. 369
Investigation 2: Describe Rates ................................................... 373
Investigation 3: Proportional Relationships .............................. 377
Inquiry Investigation 4: Rolling Along ................................... 380
On Your Own Exercises ............................................................. 382
Lesson 8.2 Speed and Slope .......................................... 389 Investigation 1: Walk and Jog ..................................................... 390
Investigation 2: Distance and Time ............................................ 394
Investigation 3: Describe Graphs ................................................ 396
Investigation 4: Change the Starting Point ............................... 398
On Your Own Exercises ............................................................. 402
Lesson 8.3 Recognize Linear Relationships ......... 410 Investigation 1: Explore and Describe Patterns ....................... 411
Investigation 2: Graphs and Rules from Patterns .................... 414
Investigation 3: From Rules to Graphs ...................................... 417
Investigation 4: Secret Rules ....................................................... 420
On Your Own Exercises ............................................................. 423
Review & Self-Assessment ...................................................... 431
▼▼G7-FP1
G7-FP3
G7-FP5C
and ConnectionsSee pages vi and vii for key.
xv
9 Equations ................................................................................ 434Lesson 9.1 Find a Solution Method ........................... 436 Investigation 1: Choose a Solution Method ............................. 437
Inquiry Investigation 2: Use a Spreadsheet to Guess-Check-and-Improve ............. 440
On Your Own Exercises ............................................................. 444
Lesson 9.2 A Model for Solving Equations ........... 446 Investigation 1: Balance Puzzles ................................................. 447
Investigation 2: Keep Things Balanced ..................................... 449
Investigation 3: Solve Problems with Balance Puzzles .......... 453
On Your Own Exercises ............................................................. 455
Lesson 9.3 Solve Equations ............................................. 460 Investigation 1: Symbolic Solutions ........................................... 461
Investigation 2: Do the Same Thing to Both Sides ................. 462
Investigation 3: Solve More Equations ...................................... 464
Investigation 4: Solve One-Variable Inequalities ..................... 466
On Your Own Exercises ............................................................. 469
Lesson 9.4 Solve Equations with Parentheses .... 474 Investigation 1: Build and Solve Equations .............................. 474
Investigation 2: Subtract with Parentheses .............................. 477
Investigation 3: More Practice with Parentheses .................... 481
On Your Own Exercises ............................................................. 484
Review & Self-Assessment ...................................................... 489
▼▼ G7-FP3
G7-FP5C
and ConnectionsSee pages vi and vii for key.
xvi
1010 Proportional Reasoning and Percents ..................................................................................... 492Lesson 10.1 Ratios ................................................................. 494 Investigation 1: Ratio and Rate Comparisons .......................... 495
Investigation 2: Compare and Scale Ratios .............................. 497
On Your Own Exercises ............................................................. 500
Lesson 10.2 Proportions and Similarity ................... 505 Investigation 1: Proportional Relationships .............................. 505
Investigation 2: Equal Ratios ....................................................... 508
Investigation 3: Solve Proportions ............................................. 510
Investigation 4: Map Scales ......................................................... 514
Investigation 5: Similarity ............................................................. 517
Inquiry Investigation 6: Estimate Heights of Tall Objects ....................................... 519
On Your Own Exercises ............................................................. 522
Lesson 10.3 Percents and Proportions .................... 530 Investigation 1: Find Percents ..................................................... 530
Investigation 2: Proportions Using Percents ............................ 534
On Your Own Exercises ............................................................. 537
Lesson 10.4 Rates ................................................................... 540 Investigation 1: Unit Prices .......................................................... 540
Investigation 2: Convert Currencies ........................................... 544
On Your Own Exercises ............................................................. 547
Review & Self-Assessment ...................................................... 551
▼▼G7-FP1
G7-FP4C
and ConnectionsSee pages vi and vii for key.
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