# Grade 3 Mathematics Lesson Plan
## Topic: Addition and Subtraction (Three-Digit Numbers)
### Duration: 60 minutes
---
### Objectives:
- Students will understand and apply addition and subtraction of three-digit numbers.
- Students will use strategies such as carrying and borrowing (regrouping) effectively.
- Students will solve word problems that involve adding and subtracting three-digit numbers.
### Materials Needed:
- Whiteboard and markers
- Base-ten blocks (or similar manipulatives)
- Worksheets with addition and subtraction problems
- Number lines
- Notebooks and pencils
- Flashcards with three-digit addition and subtraction problems
- Projector/Interactive whiteboard (for displaying examples)
### Common Core Standards:
- CCSS.MATH.CONTENT.3.NBT.A.1: Use place value understanding to round whole numbers to the nearest 10 or 100.
- CCSS.MATH.CONTENT.3.NBT.A.2: Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.
- CCSS.MATH.CONTENT.3.OA.A.3: Solve two-step word problems using addition and subtraction.
---
### Lesson Structure:
#### 1. Introduction (10 minutes)
- **Greeting and Objective Introduction:**
- Greet the class and introduce the topic for the day: Addition and Subtraction of Three-Digit Numbers.
- Explain the objectives of the lesson.
- Ask introductory questions to gauge students' prior knowledge.
- **Warm-Up Activity:**
- Have students solve a few basic two-digit addition and subtraction problems on their whiteboards.
- Discuss the strategies they used and introduce the concept of moving to three-digit numbers.
#### 2. Direct Instruction (15 minutes)
- **Addition of Three-Digit Numbers:**
- Write a three-digit addition problem on the board (e.g., 456 + 289).
- Demonstrate the addition process, emphasizing carrying over when the sum exceeds 9.
- Use base-ten blocks or number lines to visually represent the problem.
- **Subtraction of Three-Digit Numbers:**
- Write a three-digit subtraction problem on the board (e.g., 652 - 374).
- Demonstrate the borrowing process when the top digit is smaller than the bottom digit.
- Use manipulatives to show how borrowing works.
#### 3. Guided Practice (15 minutes)
- **Group Activity:**
- Divide students into small groups and provide each group with a set of base-ten blocks and worksheets containing addition and subtraction problems.
- Guide the groups to solve the problems, ensuring they use the blocks to model carrying and borrowing.
- **Interactive Questions:**
- Display problems on the projector/interactive whiteboard and have volunteers come up to solve them.
- Discuss the steps taken and clarify any misunderstandings.
#### 4. Independent Practice (10 minutes)
- **Worksheet Completion:**
- Hand out worksheets with a mix of addition and subtraction problems.
- Encourage students to solve the problems independently in their notebooks.
- Walk around the classroom to provide individual support as needed.
#### 5. Real-World Application and Word Problems (10 minutes)
- **Word Problems:**
- Present a few word problems involving three-digit addition and subtraction (e.g., "Sally had 345 apples. She bought 128 more. How many apples does she have now?").
- Work through the first problem as a class, modeling the process of extracting numbers and determining whether to add or subtract.
- Allow students to work on additional word problems in pairs or small groups.
#### 6. Closing and Review (10 minutes)
- **Review Key Points:**
- Summarize the key strategies for adding and subtracting three-digit numbers.
- Highlight the importance of checking their work by using inverse operations.
- **Exit Tickets:**
- Provide each student with a flashcard that has a three-digit addition or subtraction problem.
- Have students solve the problem and hand it in as they leave to assess their understanding.
- **Homework:**
- Assign a simple worksheet for additional practice at home or ask students to create their own three-digit problems and solve them.
### Assessment:
- Observation during guided practice.
- Completion and accuracy of independent practice worksheets.
- Correctness of answers on exit tickets.
### Differentiation:
- **For Advanced Learners:**
- Provide more challenging problems that involve multiple steps or introduce four-digit problems.
- **For Struggling Learners:**
- Offer one-on-one or small group support, using additional manipulatives and visual aids.
### Reflection:
- After the class, reflect on what worked well and what could be improved. Adjust future lessons based on student performance and feedback.
---
By carefully following this lesson plan, students will enhance their understanding and skills in adding and subtracting three-digit numbers and be able to apply these skills to real-world problems.