Contents

1. Section A: Add Within 1,000
2. Lesson 1: Represent Numbers in Different Ways
   1. Warm-up: Which One Doesn’t Belong: Numbers within 1,000
   2. 1.1: Card Sort: Numbers in Their Different Forms
   3. 1.2: Numbers in Different Forms Round Table
3. Lesson 2: Addition and Subtraction Situations
   1. Warm-up: Notice and Wonder: Two Curious Tables
   2. 2.1: Monuments and Falls
   3. 2.2: Journal About Connections
4. Lesson 3: Add Your Way
   1. Warm-up: Number Talk: Hundreds, Tens, and Ones
   2. 3.1: Strategies to Add
   3. 3.2: Two Ways to Add
5. Lesson 4: Introduction to Addition Algorithms
   1. Warm-up: Which One Doesn’t Belong: 247
   2. 4.1: What is an Algorithm?
   3. 4.2: Try an Algorithm
6. Lesson 5: Another Addition Algorithm
   1. Warm-up: Notice and Wonder: Another Curious Table
   2. 5.1: A New Addition Algorithm
   3. 5.2: Compose New Units
7. Lesson 6: Use Strategies and Algorithms to Add
   1. Warm-up: Number Talk: Little More, Little Less
   2. 6.1: Just Ones
   3. 6.2: How Would You Add?
   4. Section A Summary
   5. Section A Practice Problems
8. Section B: Subtract Within 1,000
9. Lesson 7: Subtract Your Way
   1. Warm-up: Number Talk: Subtract Two-Digit Numbers
   2. 7.1: Strategies to Subtract
   3. 7.2: Base-ten Drawings
10. Lesson 8: Subtraction Algorithms (Part 1)
    1. Warm-up: Number Talk: Subtraction Strategies
    2. 8.1: From Drawings to an Algorithm
    3. 8.2: Card Sort: Diagrams and Algorithms
11. Lesson 9: Subtraction Algorithms (Part 2)
    1. Warm-up: True or False: Does It Commute?
    2. 9.1: Revise Subtraction Work
    3. 9.2: Try the Algorithm
12. Lesson 10: Subtraction Algorithms (Part 3)
    1. Warm-up: Notice and Wonder: Digits that Disappear
    2. 10.1: A New Subtraction Algorithm
    3. 10.2: Try Clare’s Algorithm
13. Lesson 11: Analyze Subtraction Algorithms
    1. Warm-up: Number Talk: Subtract within 1,000
    2. 11.1: Compare Two Subtraction Algorithms
    3. 11.2: Use an Algorithm?
14. Lesson 12: Subtract Strategically
    1. Warm-up: Number Talk: Threes
    2. 12.1: How Would You Subtract?
    3. 12.2: Greatest Difference, Smallest Difference
    4. Section B Summary
    5. Section B Practice Problems
15. Section C: Round Within 1,000
16. Lesson 13: Multiples of 100
    1. Warm-up: Estimation Exploration: Marching Band
    2. 13.1: About 100? Close to 100?
    3. 13.2: Close to Multiples of 100
17. Lesson 14: Nearest Multiples of 10 and 100
    1. Warm-up: Estimation Exploration: What Number Could this Be?
    2. 14.1: Close to Multiples of 10
    3. 14.2: The Nearest Multiples
18. Lesson 15: Round to the Nearest Ten and Hundred
    1. 15.1: Can the Nearest Ten and Hundred be the Same?
    2. 15.2: Round to Estimate
19. Lesson 16: Round and Round Again
    1. Warm-up: Number Talk: More Groups, Fewer Groups
    2. 16.1: All the Numbers
    3. 16.2: What’s My Mystery Number?
    4. Section C Summary
    5. Section C Practice Problems
20. Section D: Solve Two-Step Problems
21. Lesson 17: Does It Make Sense?
    1. Warm-up: True or False: Is it Greater?
    2. 17.1: Quick Estimates
    3. 17.2: Solve and Reason
22. Lesson 18: Diagrams and Equations for Word Problems
    1. Warm-up: Notice and Wonder: Diagrams
    2. 18.1: Card Sort: Situations, Equations, and Diagrams
    3. 18.2: Makes Sense to Me: A Gallery Walk
23. Lesson 19: Situations and Equations
    1. Warm-up: Notice and Wonder: The Unknown
    2. 19.1: Mai’s Beads
    3. 19.2: Represent, Solve, Explain
24. Lesson 20: More Practice to Represent and Solve
    1. Warm-up: Number Talk: Two Steps
    2. 20.1: Info Gap: Introduction
    3. 20.2: Info Gap: Bake Sale
    4. Section D Summary
25. Lesson 21: Classroom Supplies
    1. Warm-up: Notice and Wonder: School Supplies List
    2. 21.1: Make a Wish List
    3. 21.2: What's on Your List?
    4. Section D Practice Problems
26. Glossary
27. Attributions
    1. Image Attributions
28. Citations
29. Notes
30. Notes