Lesson Plan | Traditional Methodology | Addition and Subtraction of Natural Numbers Less than 100

Objectives

Duration: 10 - 15 minutes

The aim of this stage of the lesson plan is to provide a clear and detailed view of what will be learned during the class. By defining specific objectives, the teacher establishes a clear direction, ensuring that both they and the students know exactly which skills will be developed. This facilitates the organization of the lesson and contributes to the students understanding the importance and applicability of the content to be taught.

Main Objectives

1. Teach students to add two-digit numbers with and without the aid of algorithms.

2. Teach students to subtract two-digit numbers with and without the aid of algorithms.

3. Teach students to solve problems involving the addition or subtraction of two-digit numbers.

Introduction

Duration: 10 - 15 minutes

The aim of this stage of the lesson plan is to spark students' interest and contextualize the theme, showing how addition and subtraction are important and present in various everyday situations. This helps make learning more meaningful and relevant for the students, increasing their motivation to learn.

Context

To start our lesson on addition and subtraction of natural numbers less than 100, let's remember some everyday situations where we need to use these operations. For example, when you go to the market with your family and need to add up the prices of products to know how much you will spend, or when you receive change and need to subtract to check if it is correct. These operations are fundamental and very useful for solving various problems we encounter in our daily lives.

Curiosities

Did you know that addition and subtraction are mathematical operations that we have used since ancient times? The ancient Egyptians, for example, already used these operations to build pyramids and organize their harvests. Nowadays, we use addition and subtraction in many areas, such as in science, engineering, and even in video games!

Development

Duration: 50 - 60 minutes

The aim of this stage of the lesson plan is to provide detailed explanations of the concepts of addition and subtraction, as well as guide students in solving problems involving these operations. By addressing each topic clearly and with practical examples, the teacher ensures that students understand and correctly apply the mathematical operations. Solving questions in class allows students to practice and consolidate their learning, ensuring a solid understanding of the content.

Covered Topics

1. Concept of Addition: Explain to students that addition is the mathematical operation that consists of combining two or more quantities. Exemplify with objects from the classroom, such as pencils or erasers. For example, 'If we have 3 pencils and add 2 more, how many pencils do we have in total?' 2. Concept of Subtraction: Detail that subtraction is the mathematical operation that consists of taking one quantity away from another. Use visual examples, such as apples drawn on the board. For example, 'If we have 5 apples and eat 2, how many apples are left?' 3. Addition with Two-Digit Numbers: Discuss how to add two-digit numbers, starting with the units and then the tens. Use examples on the board, such as '23 + 45'. Explain step by step, starting with the addition of the units (3 + 5 = 8) and then the tens (2 + 4 = 6), resulting in 68. 4. Subtraction with Two-Digit Numbers: Explain how to subtract two-digit numbers. Use examples on the board, such as '76 - 34'. Detail the process, starting with the subtraction of the units (6 - 4 = 2) and then the tens (7 - 3 = 4), resulting in 42. 5. Problem Solving: Present contextualized problems involving addition and subtraction, such as: 'If João had 50 reais and spent 23 reais at the store, how much money does he have now?' or 'Ana had 37 stickers and received 25 more from her friend. How many stickers does Ana have now?'

Classroom Questions

1. Solve: 47 + 32 2. Solve: 58 - 19 3. João had 45 candies and gave 17 to his friend. How many candies does João have now?

Questions Discussion

Duration: 15 - 20 minutes

The aim of this stage of the lesson plan is to review and reinforce learning, ensuring that all students understood the concepts of addition and subtraction of two-digit numbers. A detailed discussion of the questions allows identifying and correcting errors, promoting active participation from students and strengthening understanding through reflection and collective engagement.

Discussion

• Question 1: Solve: 47 + 32

Explanation: To solve the sum of 47 + 32, follow these steps: Add the units: 7 + 2 = 9. Add the tens: 4 + 3 = 7.

Thus, 47 + 32 = 79.

Question 2: Solve: 58 - 19

Explanation: To solve the subtraction of 58 - 19, follow these steps: Subtract the units: 8 - 9. Since 8 is less than 9, it is necessary to borrow a ten from the tens column. Thus, 18 - 9 = 9. Subtract the tens: After borrowing a ten, it becomes 4 - 1 = 3.

Thus, 58 - 19 = 39.

Question 3: João had 45 candies and gave 17 to his friend. How many candies does João have now?

Explanation: To solve this problem, perform the subtraction of 45 - 17: Subtract the units: 5 - 7. Since 5 is less than 7, it is necessary to borrow a ten. Thus, 15 - 7 = 8. Subtract the tens: After borrowing a ten, it becomes 3 - 1 = 2.

Thus, João has 28 candies now.

Student Engagement

1. Did anyone find a different answer for the sum of 47 + 32? How did you arrive at that answer? 2. Did anyone have difficulty with the subtraction of 58 - 19? Where did you find problems? 3. How can we check if our subtraction of 45 - 17 is correct? 4. In what other everyday situations do you use addition and subtraction? Can you share an example? 5. If João had given 20 candies instead of 17, how many candies would he have now? How can we calculate that?

Conclusion

Duration: 5 - 10 minutes

The aim of this stage of the lesson plan is to review and consolidate the main points addressed during the lesson, ensuring that students leave with a clear and organized understanding of the content. The conclusion also reinforces the connection between theory and practice, highlighting the relevance of learning for the students' daily lives.

Summary

• Concept of addition as the operation of combining quantities.
• Concept of subtraction as the operation of taking away quantities.
• Addition of two-digit numbers, adding units and tens separately.
• Subtraction of two-digit numbers, including borrowing tens when necessary.
• Problem solving involving addition and subtraction of two-digit numbers.

During the lesson, it was demonstrated how addition and subtraction are used in various everyday situations, such as calculating change, summing prices of products, and solving practical problems. Visual examples and contextualized problems helped connect mathematical theory with real practices, facilitating students understanding and application of concepts.

Learning addition and subtraction of two-digit numbers is fundamental for the daily life of students. These operations are used in everyday activities such as shopping, managing personal finances, and even in games and play. Knowing and mastering these operations from an early age develops important mathematical skills that will be used throughout life.