Addition and Subtraction Fluency

Overview

This 50-minute lesson is designed for a class of 21 first-grade students to build foundational addition and subtraction skills guided by Eureka Math Module 2. The lesson will integrate elements of the Next Generation Science Standards (NGSS) by encouraging reasoning, problem-solving, and the use of evidence to justify answers, bridging math with early scientific thinking practices.

---

Standards and Learning Objectives

Eureka Math Module 2 Focus

• Developing fluency with addition and subtraction within 20 using various strategies.
• Understanding part-whole relationships with addition and subtraction.

Next Generation Science Standards Alignment

• Practices:

  • Practice 2: Developing and Using Models — Represent addition and subtraction with objects or drawings.
  • Practice 3: Planning and Carrying Out Investigations — Explore different strategies to solve problems.
  • Practice 4: Analyzing and Interpreting Data — Use answers to explain reasoning.

• Crosscutting Concepts:

  • Patterns — Recognize numerical patterns in addition and subtraction.
  • Cause and Effect — Understand how adding or removing items changes quantities.

• Disciplinary Core Ideas (Mathematical Thinking):

  • Numbers and Operations in Base Ten (add and subtract within 20)

---

Learning Objectives

By the end of this lesson, students will:

1. Fluently add and subtract numbers within 20 using visual models and number sentences.
2. Use manipulatives and drawings to model addition and subtraction problems.
3. Develop verbal explanations for their solution strategies to reinforce mathematical reasoning.
4. Collaborate scientifically by discussing solutions and justifying their reasoning.

---

Materials Needed

• Counters or small objects (e.g., cubes or buttons) — 21 sets for each student
• Dry-erase boards and markers
• Number cards (0-20)
• Eureka Math printed worksheets for Module 2 Lessons 1-5
• Visual addition and subtraction charts
• Smartboard or whiteboard
• “Think, Pair, Share” prompt cards

---

Lesson Breakdown (50 minutes)

1. Warm-Up and Introduction (8 minutes)

• Activity: Number Talk
  • Teacher displays a simple addition problem (e.g., 7 + 5) on the board.
  • Students use fingers or counters for a quick mental or hands-on calculation.
  • Discuss varied strategies: counting on, making ten, decomposing numbers.
• Objective: Engage students and activate prior knowledge on addition and subtraction.

2. Exploration and Guided Practice (20 minutes)

• Activity: Using Manipulatives to Model Problems
  • Students receive a set of counters and dry-erase boards.
  • Teacher reads addition/subtraction story problems aligned with Eureka Module 2 Lessons 1-3 (e.g., “Lina has 9 apples, she gives away 4. How many does she have left?”).
  • Students model the problem with counters and draw number sentences on their boards.
  • Students pair-share their models and explain their thinking aloud.
• NGSS Connection: Developing and Using Models; Planning and Carrying Out Investigations.

3. Interactive Group Problem Solving (12 minutes)

• Activity: Small Group Card Game
  • Groups of 3-4 students draw number cards and create their own addition or subtraction problems (within 20).
  • They use counters to solve and record the equations on mini whiteboards.
  • Groups rotate to share one problem they created and explain their reasoning.
• NGSS Connection: Analyzing and Interpreting Data; Crosscutting Concept of Patterns.

4. Independent Practice and Assessment (7 minutes)

• Students complete a short worksheet from Eureka Module 2 (Lessons 4–5) with addition and subtraction problems within 20.
• Teacher circulates, gauging understanding and offering support.
• Prompts students to explain their strategies when prompted.
• Formative Assessment: Teacher notes student fluency and strategy use.

5. Reflection and Closing (3 minutes)

• Activity: Think-Pair-Share
  • Prompt: “What is one way you solved today’s problems? Why does it work?”
  • Students think for 30 seconds, share with a partner, then a few volunteers share with the class.
• Reinforce that math is like solving a mystery with different clues and strategies.

---

Differentiation Strategies

• For advanced learners: Challenge with two-step addition/subtraction within 20.
• For learners needing support: Use number lines and more concrete manipulatives, and pair with peer helpers during group activities.

---

Teacher Notes

• Embed frequent checks for understanding by observing and asking students to explain their reasoning verbally.
• Use positive reinforcement to encourage multiple strategies and respect for different problem-solving methods.
• Connect the mathematical thinking process to how scientists explore and reason with evidence in investigations.

---

This lesson plan not only builds math fluency but immerses students in authentic scientific practices by prompting them to model, investigate, interpret data, and communicate their reasoning — perfectly aligned with NGSS while delivering Eureka Math Module 2 content in an engaging, developmentally appropriate way.