### Lesson Plan: Mathematics - Addition and Subtraction of Three-Digit Numbers
**Grade:** 3
**Subject:** Mathematics
**Topic:** Addition and Subtraction (Three-Digit Numbers)
**Duration:** 60 minutes
#### Objectives:
1. Students will be able to accurately add and subtract three-digit numbers.
2. Students will understand place value for hundreds, tens, and ones.
3. Students will apply addition and subtraction strategies to solve word problems involving three-digit numbers.
#### Materials:
- Whiteboard and markers
- Place value chart
- Base ten blocks (or visual representation)
- Worksheets with addition and subtraction problems
- Pencils and erasers
- Small dry-erase boards and markers (optional)
- Number line (optional)
- Interactive educational games (online or apps) for reinforcement
#### Introduction (10 minutes):
1. **Warm-Up Activity:**
- Begin with a quick mental math warm-up. Ask students simple addition and subtraction questions involving one or two-digit numbers.
- "If you have 25 apples and you get 40 more, how many do you have in total?"
2. **Review of Key Concepts:**
- Briefly review place values (hundreds, tens, ones) using the whiteboard and place value chart.
- Explain why understanding place values is essential for addition and subtraction of larger numbers.
#### Direct Instruction (15 minutes):
1. **Addition:**
- Demonstrate how to add two three-digit numbers step-by-step.
- Example: \( 345 + 278 \)
- Break down the process:
- Add ones: \( 5 + 8 = 13 \) (write down 3 and carry over 1)
- Add tens: \( 4 + 7 = 11 \), then add the carry over: \( 11 + 1 = 12 \) (write down 2 and carry over 1)
- Add hundreds: \( 3 + 2 = 5 \), then add the carry over: \( 5 + 1 = 6 \)
- Result: \( 345 + 278 = 623 \)
2. **Subtraction:**
- Demonstrate how to subtract two three-digit numbers step-by-step.
- Example: \( 632 - 245 \)
- Break down the process:
- Subtract ones: \( 2 - 5 \) (need to borrow from tens, so 2 becomes 12, and tens column 3 becomes 2)
- Subtract tens: \( 2 - 4 \) (need to borrow from hundreds, so 2 becomes 12, and hundreds column 6 becomes 5)
- Subtract hundreds: \( 5 - 2 = 3 \)
- Result: \( 632 - 245 = 387 \)
#### Guided Practice (15 minutes):
- Hand out worksheets with a mix of addition and subtraction problems involving three-digit numbers.
- Work through 1-2 problems as a class, allowing students to come up to the board to write the steps.
- Have students complete several problems independently or in pairs while you circulate to assist and provide feedback as needed.
#### Independent Practice (10 minutes):
- Students work individually on additional problems from their worksheets.
- Provide an optional challenge problem for advanced students to solve.
#### Application (10 minutes):
- **Word Problem:**
- Read a word problem aloud to the class:
- "Sarah has 467 marbles. She buys 156 more. How many marbles does she have now? She then gives 124 marbles to her friend. How many marbles does she have left?"
- Guide students to underline the key numbers and words.
- Solve the problem step-by-step together.
#### Assessment and Closure (10 minutes):
1. **Review:**
- Quickly go over the key points of the lesson: addition and subtraction with three-digit numbers.
- Ask a few students to explain the steps in their own words.
2. **Exit Ticket:**
- Give each student a simple problem to solve on a small piece of paper or dry-erase board.
- Example: \( 532 + 146 \) or \( 789 - 354 \)
3. **Homework:**
- Assign a worksheet for additional practice at home, including a mix of problems and a couple of word problems.
#### Reflection:
- Ask students to think about the lesson and share one thing they found easy and one thing they found challenging.
#### Accommodations and Modifications:
- Provide additional visual aids or manipulatives for students who need them.
- Offer a simplified version of the problems for struggling students.
- Provide extension activities for advanced learners, such as more complex word problems or using technology for interactive practice.
---
This lesson plan addresses the key components of teaching addition and subtraction of three-digit numbers, providing a blend of direct instruction, guided practice, and independent application to cater to various learning styles and needs.