### Lesson Plan: Addition and Subtraction of Two-Digit Numbers
**Grade Level:** 2nd Grade
**Subject:** Mathematics
**Duration:** 1 hour
**Topic:** Addition and Subtraction (two-digit numbers)
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#### **Objectives:**
1. Students will understand how to add and subtract two-digit numbers.
2. Students will learn to solve addition and subtraction problems with and without regrouping.
3. Students will apply these skills to solve real-world problems.
#### **Materials:**
- Whiteboard and markers
- Number cards (0-9)
- Base ten blocks (units and tens)
- Worksheets with addition and subtraction problems
- Pencils and erasers
- Interactive math apps (optional)
- Small dry-erase boards for students (optional)
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#### **Lesson Outline:**
1. **Introduction (10 minutes):**
- **Warm-up Activity:** Give each student a small dry-erase board and a marker. Flash number cards (e.g., 34, 56) and ask students to write the number on their boards.
- **Review:** Briefly review single-digit addition and subtraction from previous lessons. Discuss the significance of place value in two-digit numbers (tens and ones).
2. **Instructional Input (15 minutes):**
- **Addition (with and without regrouping):** Explain the process step by step using base ten blocks.
- Example without regrouping: 27 + 14
- Example with regrouping: 45 + 28
- Demonstrate using the whiteboard. Show how to line up the numbers correctly, add the ones column first, and then the tens column.
- **Subtraction (with and without regrouping):** Use base ten blocks to illustrate.
- Example without regrouping: 53 - 21
- Example with regrouping: 72 - 49
- Discuss the concept of borrowing, decomposing a ten into ten ones.
3. **Guided Practice (15 minutes):**
- Provide students with a worksheet containing a mixture of addition and subtraction problems (both with and without regrouping).
- Walk around the classroom, offering individual assistance as needed.
- Encourage students to use base ten blocks if they struggle with regrouping concepts.
4. **Independent Practice (15 minutes):**
- Give another worksheet with more problems, this time slightly more challenging.
- Students should try to solve the problems on their own without using base ten blocks.
- If available, students can practice with an interactive math app that focuses on addition and subtraction of two-digit numbers.
5. **Real-world Applications (5 minutes):**
- Present a few word problems that involve addition and subtraction. For example:
- "Sarah has 34 pencils, and she buys 27 more. How many pencils does she have now?"
- "John had 58 candies, and he gave 23 to his friends. How many candies does he have left?"
- Work through one problem together as a class, then let students solve another one individually or in pairs.
6. **Closing (5 minutes):**
- Review key points of the lesson. Highlight the importance of lining up numbers by their place value.
- Ask a few students to share one new thing they learned.
- Collect worksheets to assess understanding.
#### **Assessment:**
- **Formative:** Observe students during guided and independent practice to note who might need extra help.
- **Summative:** Evaluate the worksheets and real-world application problems to assess students' understanding and proficiency.
#### **Differentiation:**
- **For advanced students:** Provide more challenging problems that involve three-digit numbers or multi-step word problems.
- **For struggling students:** Offer additional support with base ten blocks or one-on-one assistance. Simplified problems can also be provided.
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This lesson plan aims to build a foundational understanding of adding and subtracting two-digit numbers through interactive, guided, and independent activities.