- Section A: Develop Fluency with Addition and Subtraction within 10
- Warm-up: Notice and Wonder: Addition Table
- 1.1: My Favorite Sum
- 1.2: Sums I’ve Got

- Warm-up: Number Talk: 2 or 3 More
- 2.1: More Shake and Spill
- 2.2: Are They Both Right?
- 2.3: Practice Addition within 10

- Warm-up: How Many Do You See: Sums within 10
- 3.2: Are Both Sides Equal?

- Warm-up: True or False: Equal Expressions
- 4.2: All The Ways To Make 10
- 4.3: Centers: Choice Time

- Warm-up: Number Talk: Missing Value Within 10
- 5.1: Different Ways to Find the Difference
- 5.2: Subtraction Number Strings
- 5.3: The Value of the Difference

- Warm-up: Notice and Wonder: Han's Cup
- 6.1: A Shake and Spill Story Problem
- 6.2: Shake and Spill Story Problems
- Section A Summary

- 7.2: Centers: Choice Time
- Section A Practice Problems

- Section B: Add and Subtract using Ten as a Unit
- Warm-up: Which One Doesn’t Belong: Groups of 10
- 8.2: Building Teen Numbers

- Warm-up: Notice and Wonder: Teen Numbers
- 9.1: Make It: Teen Numbers and 10-Frames
- 9.2: Equations With a Ten

- Warm-up: Number Talk: A Ten and Some Ones
- 10.1: Story Problems With a Ten
- 10.2: Related Equations

- Warm-up: True or False: Teen Numbers
- 11.1: Rock Collection
- 11.2: Write Equations: Adding on to Teen Numbers
- 11.3: Centers: Choice Time

- 12.1: Noah’s Collection
- 12.2: Addition and Subtraction Equations with Teen Numbers

- Warm-up: Number Talk: Add Ones
- 13.1: Sitting or Standing
- 13.2: Solve Story Problems and Compare Methods
- 13.3: Centers: Choice Time
- Section B Summary

- Warm-up: True or False: Expressions on Both Sides
- 14.2: Centers: Choice Time
- Section B Practice Problems

- Section C: Add within 20
- Warm-up: How Many Do You See: 10-frames
- 15.1: Louis Agassiz Fuertes’s Birds
- 15.2: Fuertes’s Bird Cards

- Warm-up: Number Talk: Related Expressions
- 16.1: Match Expressions
- 16.2: Is the Equation True?
- 16.3: Write Expressions

- Warm-up: How Many Do You See: Double 10-frames
- 17.1: The 9 Plus Game
- 17.2: Clare’s Birds

- Warm-up: How Many Do You See: More Double 10-frames
- 18.1: Expression Match
- 18.3: Centers: Choice Time

- Warm-up: Number Talk: Related Expressions
- 19.1: Lin, Han, and Kiran Add
- 19.2: How Did You Add?

- Warm-up: Number Talk: Using 10 + \boxed{\phantom{4}}
- 20.1: How Many Reptiles?
- 20.2: Zoo Exhibits
- Section C Summary

- Warm-up: What Do You Know About 20?
- Section C Practice Problems

- Section D: Subtract within 20
- Warm-up: Number Talk: Subtract from a Teen Number
- 22.1: Subtraction Methods
- 22.2: Number Card Subtraction

- Warm-up: Number Talk: Subtract to Make 10
- 23.1: Number Card Subtraction with 10-frames
- 23.2: Diego and Andre Find the Difference

- 24.1: Different Ways to Subtract
- 24.2: Find the Number That Makes Each Equation True

- 25.1: Choose Your Own Subtraction Method
- 25.2: Solve Story Problems

- Warm-up: Number Talk: Subtract 10 or More
- 26.1: Solve Related Story Problems
- 26.2: More Story Problems
- Section D Summary

- Warm-up: Number Talk: Subtract 10
- 27.2: Introduce Compare, Add and Subtract Within 20

- Warm-up: Notice and Wonder: Counting Things in the Classroom
- 28.1: Writing Classroom Story Problems
- 28.3: Poster Gallery Walk
- Section D Practice Problems

- Glossary
- Image Attributions

- Citations
- Notes
- Notes