Components of the Program

think! Mathematics Teacher Resource Materials is a printed teacher guide that is based on various learning theories. 

Designed in accordance with extensively-researched approaches used in Singapore, these books adopt a spiral design with the integration of the Concrete-Pictorial-Abstract (C-P-A) approach.

A three-part lesson structure of Anchor Task, Guided Practice and Independent Practice are adopted. ICT, concrete aids and manipulatives are incorporated. Students have opportunities to hone problem-solving skills and apply Mathematics in real-world contexts.

Combining the effectiveness of teaching pedagogies and innovative ideas, the content has been aligned to the Common Core State Standards.

Teacher Resource Materials Book A $150.00 

Teacher Resource Materials Book B $150.00 

Shop Now

Essential Digital Teacher’s Resource Materials includes:

    • Digital Teacher Guide A & B
    • Digital Student Textbook A & B
    • Digital Student Workbook A & B

This product can only be purchased by accounts located within the United States.

Digital Teacher Resources are available for teachers who have purchased a classroom set of textbooks or workbooks for the current school year.

Essential Digital Teacher Resource  *$49.99/teacher

 *1-year subscription 

Shop Now

  • Subscription to think!Mathematics Digital Teacher’s Resource Materials
    • Teacher Guide A & B
    • Student Textbook A & B
    • Student Workbook A & B
  • Digital Online Question Bank-Question bank allows the teacher to create assessments, exit tickets, journal questions by dragging dropping questions that meet one’s objective
  • Printable Chapter Assessment
  • Curriculum Maps- Curriculum maps for each chapter outline the Common Core alignment, stage within the learning cycle, and vertical alignment for conceptual development of content
  • Learning Goals and Scales-Provides checklist for student self-reflection with each chapter
  • Home Links- Team up with home by providing goals, vocabulary, methods of solving, and practice games for each chapter
  • Teacher Video Library- Chapter by Chapter videos that capture the key ideas for delivering content
  • *Student Resources-Chapter by Chapter video support bundled with downloads, journal prompts, activities, and more
  • Teacher downloads for each chapter
  • Photos of our young mathematicians in action

*Price includes up to 20 student logins

This product can only be purchased by accounts located within the United States.

Digital Teacher Resources are available for teachers who have purchased a classroom set of textbooks or workbooks for the current school year.

Premium Digital Teacher Resource  *$249.99/teacher

 *1-year subscription runs July 2020-June 2021 

Shop Now

Lessons begin with an Anchor Task  problem for students to explore.  The anchor task provides opportunity for the students to explore BEFORE structured learning takes place.  Each anchor task is designed to support struggling learners as well as extend the learning of advanced thinkers.

The Let’s Learn provides opportunities for students to read and reflect on the methods raised during the class discussion.

Guided Practice offers scaffolded questions to further consolidate the learning and assess student learning.

Each chapter includes activities, a mind workout, math journal, and self-check.

Student Textbook A (Hardcover) $19.90 

Student Textbook B (Hardcover) $19.90 

Shop Now

Each lesson has a corresponding workbook page with well structured problem sets that meet the lesson objectives.

Workbooks also include Mind Workout exercises that provide enrichment for students to apply relevant heuristics and extend the concepts and skills learned.

Reviews follow each chapter where Cumulative Reviews occur after every three to four chapters.

Student Workbook A $11.90 

Student Workbook B $11.90 

Shop Now

Back by popular demand! 

Similar in format to Online Learning instruction we offered this spring, the student resource package offers explorations, practice and reflection opportunities by topics covered in think!Mathematics.  Students are able to choose the content to match students’ learning needs. Designed for remote instruction and organized around the 3-Part lesson structure, students will be able to follow lesson on their own! We have incorporated the tasks from the student textbooks, practice from the student workbook, and additional math activities, books, and printable journal prompts.  If you are looking for rich mathematics that engages students on a level apart from that of completing  workbook pages you have come to the right place!  

Student Resource Package is available to classrooms that have purchased a classroom set of textbooks or workbooks for the current school year.

Access codes are assigned by classroom teachers.

Teacher Guide

  • Teacher Resource Materials

Student Books

  • Student Textbook

think!Mathematics Scope and Sequence

Grade 1

Book A

Numbers to 10

  1. Counting 
  2. Counting Things
  3. Counting Things 
  4. Learning about Zero
  5. Comparing Numbers of Things
  6. Comparing Numbers 
  7. Ordering Numbers 

Number Bonds

  1. Making Number Bonds
  2. Making Number Stories

Addition Within 10

  1. Adding by Counting All
  2. Adding by Counting On 
  3. Completing Number Sentences
  4. Making Addition Stories
  5. Solving Picture Problems

Subtraction Within 10

  1. Subtracting by Crossing Out 
  2. Subtracting by Using Number Bonds
  3. Subtracting by Counting Back 
  4. Making Subtraction Stories
  5. Solving Picture Problems
  6. Making Fact Families

Positions and Ordinal Numbers

  1. Naming Positions in Races
  2. Naming Positions in Lines
  3. Naming Positions in a Row

Numbers to 20

  1. Counting
  2. Counting
  3. Comparing Numbers
  4. Ordering Numbers
  5. Making Number Patterns
  6. Making Number Patterns

Addition and Subtraction Within 20

  1. Adding by Counting On
  2. Adding by Making 10
  3. Adding by Adding Ones
  4. Subtracting by Counting Back
  5. Subtracting by Subtracting Ones
  6. Subtracting from 10
  7. Making Facts Families
  8. Adding Three Numbers

Shapes

  1. Naming Three-Dimensional Shapes
  2. Grouping Three-Dimensional Shapes
  3. Making Patterns with Three-Dimensional Shapes
  4. Creating Three-Dimensional Shapes
  5. Naming Two-Dimensional Shapes
  6. Grouping Two-Dimensional Shapes
  7. Making Patterns with Two-Dimensional Shapes
  8. Creating Two-Dimensional Shapes
  9. Making Halves
  10. Making Fourths

Book B

Numbers to 40

  1. Counting to 30
  2. Counting to 40 
  3. Counting to 40 
  4. Comparing and Ordering Numbers
  5. Finding How Much More or Less
  6. Finding How Much More or Less
  7. Making Number Patterns

Addition and Subtraction Word Problems

  1. Solving Word Problems
  2. Solving Word Problems
  3. Solving Word Problems
  4. Solving Word Problems
  5. Solving Word Problems
  6. Solving Word Problems

Numbers to 120

  1. Counting to 100
  2. Counting to 100
  3. Finding Place Value
  4. Partitioning Numbers
  5. Comparing and Ordering Numbers
  6. Finding How Much More or Less
  7. Making Number Patterns
  8. Making Number Patterns
  9. Counting to 120

Addition and Subtraction within 100

  1. Making Families of Addition and Subtraction Facts
  2. Simple Adding
  3. Simple Subtracting
  4. Simple Adding
  5. Simple Adding
  6. Simple Subtracting
  7. Adding with Regrouping
  8. Adding with Regrouping
  9. Subtracting with Regrouping

Length and Height

  1. Comparing Length and Height
  2. Measuring Length 
  3. Measuring Length and Height

Time

  1. Telling Time to the Hour
  2. Telling Time to the Half Hour
  3. Telling Time using Digital Clocks
  4. Using Next, Before, and After
  5. Using a Calendar

Money

  1. Recognizing Coins
  2. Counting Money

Data

  1. Making Lists, Tables, and Picture Graphs
  2. Making and Reading Picture Graphs
  3. Tally Charts and Picture Graphs

Grade 2

Book A

Numbers to 1000

  1. Counting by Hundreds
  2. Counting by Hundreds, Tens, and Ones
  3. Finding PLace Value
  4. Comparing and Ordering Numbers
  5. Making Number Patterns
  6. Making Number Patterns

Addition Within 1000

  1. Adding 1-Digit Numbers
  2. Adding 2-Digit Numbers
  3. Simple Adding
  4. Simple Adding
  5. Simple Adding
  6. Adding with Regrouping
  7. Adding with Regrouping
  8. Adding with Regrouping
  9. Adding with Regrouping
  10. Adding with Regrouping

Subtraction With 1000

  1. Simple Subtracting
  2. Simple Subtracting
  3. Simple Subtracting
  4. Simple Subtracting
  5. Simple Subtracting
  6. Subtracting with Regrouping
  7. Subtracting with Regrouping
  8. Subtracting with Regrouping
  9. Subtracting with Regrouping
  10. Subtracting with Regrouping

Multiplication

  1. Making Equal Groups
  2. Adding Equal Groups
  3. Making Equal Rows
  4. Multiplying 2
  5. Finding Doubles
  6. Multiplying 5
  7. Multiplying 10
  8. Multiplying 3 and 4
  9. Solving Word Problem

Multiplication and Division

  1. Grouping
  2. Sharing
  3. Dividing as Grouping
  4. Dividing as Sharing
  5. Dividing as Grouping and Sharing
  6. Multiplying and Dividing
  7. Recognizing Odd and Even Numbers
  8. Recognizing Odd and Even Numbers
  9. Solving Word Problems

Addition and Subtraction Word Problems

  1. Solving One-Step Word Problems
  2. Solving One-Step Word Problems
  3. Solving One-Step Word Problems
  4. Solving One-Step Word Problems
  5. Solving Two-Step Word Problems
  6. Solving Two-Step Word Problems
  7. Solving Two-Step Word Problems
  8. Solving Two-Step Word Problems

Book B

Two-Dimensional Shapes

  1. Identifying Sides
  2. Identifying Vertices
  3. Identifying Angles
  4. Sorting Shapes
  5. Drawing Shapes
  6. Making Patterns
  7. Creating Shapes
  8. Partitioning Shapes

Three-Dimensional Shapes

  1. Describing Shapes
  2. Describing Shapes
  3. Sorting Shapes
  4. Making Patterns
  5. Forming Three-Dimensional Shapes

Fractions

  1. Making Equal Parts
  2. Showing Half
  3. Showing Quarters or Fourths
  4. Showing Thirds
  5. Showing Eighths

Length and Height Using the Metric System

  1. Measuring Length and Height Using a Ruler
  2. Measuring Length and Height in Meters
  3. Measuring Length and Height in Centimeters
  4. Comparing Length in Meters
  5. Comparing Length and Height in Centimeters
  6. Estimating Length and Height in Meters and Centimeters
  7. Solving One-Step Word Problems
  8. Solving Two-Step Word Problems

Length and Height Using Customary Units of Measurement

  1. Measuring Length and Height in Feet
  2. Measuring Length and Height in Yards
  3. Measuring Length and Height in Inches
  4. Measuring Length in Inches
  5. Comparing Length and Height
  6. Estimating Length in Yards, Feet, and Inches 

Time

  1. Telling and Writing Time
  2. Telling and Writing Time
  3. Telling the Time
  4. Telling the Time
  5. Solving Problems

Money

  1. Counting Money
  2. Counting Money
  3. Counting Money
  4. Recognizing Bills
  5. Counting Money
  6. Adding Money
  7. Adding and Subtracting Money
  8. Adding Money
  9. Adding and Subtracting Money
  10. Adding Money
  11. Adding and Subtracting Money
  12. Solving Word Problems

Data

  1. Reading Picture Graphs
  2. Drawing Picture Graphs
  3. Drawing Bar Graphs
  4. Reading Bar Graphs
  5. Drawing Line Plots
  6. Reading Line Plots

Numbers to 1200

  1. Counting by Hundreds
  2. Counting by Hundreds, Tens, and Ones

Grade 3

Book A

Numbers to 10,000

  1. Counting up to 1,000
  2. Counting by Thousands
  3. Counting by Thousands, Hundreds, Tens, and Ones
  4. Using Place Value
  5. Using Place Value
  6. Comparing and Ordering Numbers
  7. Comparing and Ordering Numbers
  8. Making Number Patterns
  9. Making Number Patterns
  10. Making Number Patterns
  11. Rounding Numbers
  12. Rounding Numbers

Addition and Subtraction Within 1,000

  1. Estimating Sums
  2. Simple Adding
  3. Adding with Regrouping
  4. Adding Using Mental Strategies
  5. Choosing Strategies for Addition
  6. Estimating Differences
  7. Simple Subtracting
  8. Subtraction with Regrouping
  9. Subtraction with Regrouping
  10. Subtraction with Regrouping
  11. Choosing Strategies for Subtraction

Multiplication and Division

  1. Multiplying 0 and 1
  2. Dividing by 1
  3. Multiplying 3 and 4
  4. Multiplying 6
  5. Dividing by 6
  6. Multiplying 7
  7. Dividing by 7
  8. Multiplying 4 and 8
  9. Dividing by 8
  10. Multiplying 9
  11. Dividing by 9
  12. Solving Word Problems
  13. Solving Word Problems

More Multiplication and Division

  1. Multiplying 2-Digit Numbers
  2. Multiplying 2-Digit Numbers
  3. Multiplying 2-Digit Numbers
  4. Multiplying 2-Digit Numbers with Regrouping
  5. Multiplying 2-Digit Numbers with Regrouping
  6. Multiplying 2-Digit Numbers with Regrouping
  7. Multiplying Three Numbers
  8. Dividing 2-Digit Numbers
  9. Dividing 2-Digit Numbers
  10. Dividing 2-Digit Numbers with Regrouping
  11. Dividing 2-Digit Numbers with Regrouping
  12. Multiplying 3-Digit Numbers
  13. Dividing 3-Digit Numbers
  14. Recognizing Odd and Even Numbers

Word Problems with Mixed Operations

  1. Solving Word Problems
  2. Solving Word Problems
  3. Solving Word Problems
  4. Solving Word Problems
  5. Solving Word Problems
  6. Solving Word Problems
  7. Solving Word Problems
  8. Solving Word Problems

Fractions

  1. Showing Fractions
  2. Making Equal Fractions
  3. Making Equal Fractions
  4. Finding Equivalent Fractions
  5. Comparing Fractions
  6. Comparing Fractions
  7. Solving Word Problems

Length Height

  1. Measuring Length 
  2. Measuring Height

Book B

Time

  1. Telling Time
  2. Comparing Time
  3. Comparing Time
  4. Measuring Time in Minutes
  5. Measuring Time in Minutes
  6. Solving Word Problems
  7. Solving Problems
  8. Solving Word Problems

Money

  1. Solving Problems
  2. Solving Word Problems
  3. Solving Problems
  4. Solving Word Problems

Mass

  1. Estimating Mass
  2. Measuring Mass in Kilograms
  3. Measuring Mass in Grams
  4. Reading Weighing Scales
  5. Reading Weighing Scales
  6. Solving Word Problems
  7. Solving Word Problems

Volume

  1. Estimating Volume
  2. Measuring Mass in Liters
  3. Solving Word Problems
  4. Solving Word Problems

Geometry

  1. Sorting Shapes
  2. Describing Shapes
  3. Describing Shapes
  4. Recognizing Quadrilaterals
  5. Drawing Quadrilaterals

Perimeter of Figures

  1. Measuring Length Around a Figure
  2. Measuring Perimeter
  3. Measuring Perimeter
  4. Solving Problems
  5. Solving Problems
  6. Solving Problems

Area of Figures

  1. Measuring the Surface that an Object Covers
  2. Measuring Area
  3. Measuring Area
  4. Measuring Area
  5. Measuring Area
  6. Measuring Area
  7. Measuring Area
  8. Solving Problems

Data

  1. Making and Reading Picture Graphs
  2. Making and Reading Picture Graphs
  3. Reading Bar Graphs
  4. Reading Bar Graphs
  5. Drawing and Reading Picture Graphs and Bar Graphs
  6. Drawing Line Plots

Numbers to 100,000

  1. Counting up to 100,000
  2. Counting up to 100,000

Grade 4

Book A

Numbers to 1,000,000

  1. Reading and Writing Numbers to 100,000
  2. Reading and Writing Numbers to 100,000
  3. Comparing Numbers
  4. Comparing and Ordering Numbers
  5. Comparing Numbers
  6. Making Number Patterns
  7. Rounding Numbers
  8. Rounding Numbers
  9. Rounding Numbers

Addition and Subtraction within 1,000,000

  1. Simple Adding
  2. Adding with Regrouping
  3. Adding with Regrouping
  4. Simple Subtracting
  5. Subtracting with Regrouping
  6. Subtracting with Regrouping

Multiplication and Division

  1. Multiplying Multiples of 100
  2. Multiplying 3-Digit Numbers
  3. Multiplying 3-Digit Numbers
  4. Multiplying 4-Digit Numbers
  5. Multiplying 4-Digit Numbers
  6. Multiplying 4-Digit Numbers
  7. Multiplying a 2-Digit Number by a 2-Digit Number
  8. Multiplying a 2-Digit Number by a 2-Digit Number
  9. Dividing by 10 and 100
  10. Dividing 3-Digit Numbers
  11. Dividing 3-Digit and 4-Digit Numbers
  12. Dividing with Remainder
  13. Dividing with Remainder
  14. Finding Multiples
  15. Finding Factors
  16. Finding Prime Numbers
  17. Finding Prime Numbers

Word Problems with Mixed Operations

  1. Solving Word Problems
  2. Solving Word Problems
  3. Solving Word Problems

Fractions

  1. Finding Equivalent Fractions
  2. Finding Equivalent Fractions
  3. Finding Equivalent Fractions
  4. Finding Equivalent Fractions
  5. Comparing Fractions
  6. Comparing Fractions
  7. Comparing and Ordering Fractions
  8. Writing Mixed Numbers
  9. Showing Mixed Numbers on a Number Line
  10. Writing Improper Fractions and Mixed Numbers

Addition and Subtraction of Fractions

  1. Adding Fractions
  2. Adding Fractions
  3. Adding Fractions
  4. Adding Fractions
  5. Adding Fractions
  6. Adding Mixed Numbers
  7. Subtracting Fractions
  8. Subtracting Fractions
  9. Subtracting Fractions
  10. Subtracting Fractions
  11. Subtracting Mixed Numbers
  12. Subtracting Mixed Numbers
  13. Solving Word Problems
  14. Solving Word Problems

Multiplication of Fractions

  1. Finding Fractions of a Number
  2. Finding Fractions of a Quantity
  3. Multiplying Fractions by Whole Numbers
  4. Multiplying Mixed Numbers by Whole Numbers
  5. Solving Word Problems

Book B

Decimals

  1. Reading and Writing Tenths
  2. Reading and Writing Hundredths
  3. Writing Fractions as Decimals
  4. Reading and Writing Tenths
  5. Reading and Writing Hundredths
  6. Comparing Decimals
  7. Comparing Decimals
  8. Comparing and Ordering Decimals
  9. Adding and Subtracting Decimals

Money

  1. Writing Amounts of Money
  2. Adding Money
  3. Subtracting Money
  4. Subtracting Money
  5. Solving Problems 
  6. Solving Problems

Time

  1. Telling Time
  2. Measuring Time in Hours and Minutes
  3. Solving Problems Involving Hours and Minutes
  4. Solving Problems Involving Hours and Minutes
  5. Measuring Time in Seconds
  6. Measuring Time in Seconds
  7. Solving Problems Involving Minutes and Seconds
  8. Solving Problems Involving Minutes and Seconds
  9. Solving Problems Involving Months, Weeks , and Days

Length, Volume and Mass

  1. Measuring Length and Height in Feet and Inches
  2. Measuring Height and Length in Meters and Centimeters
  3. Measuring Length in Kilometers and Meters
  4. Solving Problems
  5. Solving Problems
  6. Measuring Mass in Pounds and Ounces
  7. Solving Problems
  8. Solving Problems
  9. Measuring Mass in Kilograms and Grams
  10. Measuring Mass in Kilograms and Grams
  11. Measuring Volume in Milliliters
  12. Measuring Volume in Milliliters
  13. Measuring Volume in Liters and Milliliters
  14. Solving Problems
  15. Solving Problems

Geometry

  1. Identifying Right Angles
  2. Measuring Angles
  3. Measuring and Comparing Angles
  4. Drawing Perpendicular Lines
  5. Drawing Lines and Angles
  6. Drawing Lines and Angles
  7. Identifying and Drawing Parallel Lines
  8. Sorting Triangles
  9. Sorting Quadrilaterals
  10. Identifying Lines of Symmetry
  11. Drawing Lines of Symmetry

Perimeter and Area of Figures

  1. Measuring Perimeter
  2. Measuring Perimeter
  3. Finding Lengths of Sides
  4. Finding Lengths of Sides of Rectangles 
  5. Investigating Perimeter
  6. Measuring Area
  7. Measuring Area of Rectangles
  8. Measuring Area of Rectangles
  9. Finding Lengths of Sides of Squares and Rectangles
  10. Estimating Area

Data

  1. Reading Line Plots
  2. Drawing Line Plots

Grade 5

Book A

Numbers to 10,000,000

  1. Reading and Writing Numbers to 10,000,000
  2. Reading and Writing Numbers to 10,000,000
  3. Comparing Numbers
  4. Comparing and Ordering Numbers
  5. Rounding NumbersUsing Mixed Operations

Four Operations on Whole Numbers

  1. Using Mixed Operations
  2. Using Mixed Operations
  3. Multiplying by Powers of 10
  4. Multiplying by 2-Digit Numbers
  5. Multiplying by 2-Digit Numbers
  6. Multiplying by 2-Digit Numbers
  7. Multiplying by 2-Digit Numbers
  8. Multiplying by 2-Digit Numbers
  9. Multiplying by 2-Digit Numbers
  10. Multiplying by 2-Digit Numbers
  11. Dividing by 2-Digit Numbers
  12. Dividing by 2-Digit Numbers
  13. Dividing by 2-Digit Numbers
  14. Dividing by 2-Digit Numbers
  15. Dividing by Powers of 10

Addition and Subtraction of Fractions

  1. Adding Fractions
  2. Adding Fractions
  3. Adding Fractions
  4. Subtracting Fractions
  5. Subtracting Fractions
  6. Subtracting Fractions
  7. Adding and Subtracting Fractions
  8. Adding and Subtracting Fractions
  9. Adding and Subtracting Fractions
  10. Adding and Subtracting Fractions

Multiplication and Division of Fractions

  1. Multiplying Fractions
  2. Multiplying Fractions
  3. Multiplying Fractions
  4. Multiplying Fractions
  5. Multiplying Fractions
  6. Dividing to Make Fractions
  7. Dividing Fractions by Whole Numbers
  8. Dividing Unit Fractions by Whole Numbers
  9. Dividing Whole Numbers by Unit Fractions

Decimals

  1. Reading and Writing Thousandths
  2. Reading and Writing Thousandths
  3. Showing Numbers on Number Lines
  4. Comparing Decimals
  5. Comparing Decimals
  6. Comparing Decimals
  7. Rounding Decimals
  8. Rounding Decimals
  9. Rounding Decimals

Four Operations on Decimals

  1. Adding and Subtracting Decimals
  2. Adding and Subtracting Decimals
  3. Adding and Subtracting Decimals
  4. Adding and Subtracting Decimals
  5. Multiplying Decimals
  6. Multiplying Decimals
  7. Multiplying Decimals
  8. Multiplying Decimals
  9. Multiplying a Decimal by a 2-Digit Whole Number
  10. Dividing Decimals
  11. Dividing Decimals
  12. Dividing Decimals
  13. Dividing a Decimal by a 2-Digit Whole Number
  14. Dividing Decimals
  15. Dividing a Decimal by a 2-Digit Whole Number

Solving Word Problems

  1. Solving Word Problems
  2. Solving Word Problems
  3. Solving Word Problems
  4. Solving Word Problems
  5. Solving Word Problems
  6. Solving Word Problems
  7. Solving Word Problems

Book B

Time

  1. Converting Units of Time
  2. Converting Units of Time
  3. Solving Word Problems

Length, Volume, Mass

  1. Measuring Length in Centimeters and Millimeters
  2. Converting Units of Length
  3. Converting Units of Length
  4. Converting Units of Length
  5. Converting Units of Length
  6. Converting Units of Length
  7. Converting Units of Mass
  8. Converting Units of Mass
  9. Converting Units of Mass
  10. Solving Word Problems
  11. Measuring Volume
  12. Measuring Volume
  13. Converting Units of Volume
  14. Converting Units of Volume
  15. Solving Word Problems

Geometry

  1. Describing Positions
  2. Describing Positions
  3. Sorting Two-Dimensional Shapes
  4. Sorting Two-Dimensional Shapes

Volume of Solids

  1. Understanding the Volume of Solids
  2. Finding Volume of Solids
  3. Finding Volume of Solids
  4. Finding Capacity of Rectangular Boxes
  5. Finding Capacity of Rectangular Boxes
  6. Solving Problems
  7. Solving Problems
  8. Solving Problems
  9. Solving Problems

Data

  1. Drawing and Reading Line Plots
  2. Reading Line Plots
  3. Drawing and Reading Line Graphs
  4. Reading Line Graphs

Algebra

  1. Describing a Pattern
  2. Describing a Pattern
  3. Describing a Pattern
  4. Writing Algebraic Expressions
  5. Solving Problems