Objectives (5 - 10 minutes)

1. Understand the concept of composition and decomposition of natural numbers less than 100.
2. Identify and describe the parts of a natural number, as well as its total sum.
3. Solve simple mathematical problems involving the composition and decomposition of natural numbers less than 100.

The objectives above should be presented in a clear and understandable way for the students, with practical examples and everyday situations. They should understand that composition refers to putting parts together to form a whole, while decomposition refers to dividing a whole into smaller parts.

Introduction (10 - 15 minutes)

1. Concept Review: The teacher should start the lesson by reminding students about the concept of natural numbers and their representation on a number line. Additionally, addition and subtraction of numbers less than 100, which are fundamental skills for understanding composition and decomposition, should be reviewed. Review activities such as addition and subtraction games using manipulatives like colored beads or sticks are suggested.

2. Problem Situations: Next, the teacher will present two problem situations that will be solved during the lesson, stimulating logical thinking and the application of mathematical concepts. The situations can be as follows:

• 'João has 74 stickers and wants to divide them equally among his 3 friends. How can João do this fairly?'
• 'Maria has 50 reais and wants to buy a toy that costs 37 reais. Does she have enough money? If so, how much will she have left?'

3. Contextualization: The teacher should explain that the composition and decomposition of numbers are important skills for everyday life, as they help solve problems more effectively. For example, when shopping, it is necessary to know how much money one has and how much will be spent. Similarly, when sharing something with friends, it is important to divide it fairly. The teacher can provide more practical examples of how we use these skills in daily life.

4. Topic Introduction: To introduce the topic of composition and decomposition of numbers, the teacher can use a playful and interesting approach for the students. For example, a 'numeric puzzle' can be presented, where students receive a certain number of sticks and must figure out how many different ways they can form a specific number. Another fun activity is the 'candy machine', where students receive a certain amount of candies and must think of different ways to share them equally with their peers. Both activities promote the idea of composition and decomposition in a practical and visual way.

Development (20 - 25 minutes)

The teacher should choose one of the following activities to be carried out in the classroom. Each activity should be adapted to the students' age group and the available class time.

1. Activity: 'House of Numbers'

• Preparation: The teacher should prepare numbered cards from 1 to 100 in advance and spread them on the classroom floor, forming a 'house of numbers'. Each card should contain a single number.
• Development: Students, in groups of up to five, should be invited to enter the 'House of Numbers' and choose three cards. With the cards in hand, they should return to their desks and then decompose each of the numbers on their cards into two or more parts. For example, if a group draws cards 24, 50, and 76, they can decompose the number 24 into 20 and 4, the number 50 into 40 and 10, and the number 76 into 70 and 6. They should record their decompositions on a piece of paper.
• Objective: This activity aims to help students visualize the idea of number decomposition in a playful and practical way. They will have to think of different ways to divide the number, reinforcing the concept of decomposition.

2. Activity: 'Candy Machine'

• Preparation: The teacher should prepare a box of assorted candies and divide them into equal quantities. For example, if the box contains 30 candies, they can be divided into 3 groups of 10 candies.
• Development: The teacher explains that each group of students represents a 'candy machine' and they must divide the quantity of candies they have equally. After dividing, they should count and record how many candies each group received. Then, they should solve a series of problems proposed by the teacher, involving the composition and decomposition of the candy numbers. For example, 'If each candy machine has 10 candies and I want to buy 25 candies, how many candy machines should I buy?'
• Objective: This activity aims to help students understand the idea of composition and decomposition of numbers in a concrete and practical way, using an example from their daily lives.

These activities should be aligned with the lesson content and provide the opportunity for students to apply the concepts of composition and decomposition of numbers in a practical and fun way. The teacher should move around the groups, assisting and clarifying doubts as needed.

Feedback (10 - 15 minutes)

1. Group Discussion: The teacher should gather all students in a large circle for a group discussion. Each group should share one of their solutions or discoveries from the activity, explaining how they composed or decomposed the numbers. The teacher should encourage students to explain their strategies and listen attentively to their peers' strategies. During the discussion, the teacher should ask questions to verify the students' understanding of the topic, such as 'Why did you choose these parts to compose the number?' or 'Why did you divide the number in this way?'. This group discussion will help consolidate learning and promote the exchange of ideas among students.

2. Connection to Theory: After the discussion, the teacher should review the concepts of composition and decomposition of numbers, reinforcing how these skills are applied in the activities the students performed. This can be done through practical examples using the numbers the students used during the activities. The teacher can also provide a quick recap of the main points of the lesson to ensure all students understand what was taught.

3. Reflection: To conclude the lesson, the teacher should propose that students reflect for a minute on what they have learned. Two simple questions can guide the reflection:

• 'How did today's activities help you better understand the composition and decomposition of numbers?'
• 'How can you apply what you learned today in real-life situations?'

Students should be encouraged to share their reflections if they feel comfortable. The teacher should listen attentively to the students' responses and reinforce the main ideas of the lesson, highlighting the relevance and applicability of the content learned.

4. Feedback: Finally, the teacher should provide overall feedback on the lesson, praising the efforts and achievements of the students, and highlighting areas that still need reinforcement. The teacher should emphasize that practice is essential for learning mathematics, and that students should continue to practice the composition and decomposition of numbers at home. The teacher can suggest some extra activities for students to practice more, such as board games involving addition and subtraction, or math problems to solve at home.

This feedback is a crucial part of the lesson plan, as it allows the teacher to assess students' understanding of the topic and plan future activities accordingly. Additionally, it helps reinforce learning and motivate students to continue learning.

Conclusion (5 - 10 minutes)

1. Recapitulation: The teacher should start the conclusion of the lesson by recapping the main points discussed. They should remind students about the definition of composition and decomposition of natural numbers less than 100 and how they can use these concepts to solve mathematical problems. This can be done through a quick review of the examples used during the lesson, asking students to remember how they solved each of them.

2. Theory and Practice Connection: Next, the teacher should emphasize the importance of the lesson and how it connects to the students' everyday lives. They can reinforce that the composition and decomposition of numbers are essential skills for solving daily problems, such as shopping, sharing items equally with friends, among others. Additionally, the teacher can mention that many everyday activities, such as games, playtime, and even watching a movie, can involve the composition and decomposition of numbers.

3. Extra Materials: The teacher should then suggest some extra materials for students to deepen their understanding of the topic covered. They can recommend children's math books that explore the concept of composition and decomposition in a playful and fun way. Additionally, the teacher can suggest educational websites and online games that offer interactive activities on the subject.

4. Importance of the Subject: Finally, the teacher should emphasize the importance of what was learned and how it can contribute to the overall development of the students. They can explain that mathematics is not just a school subject, but a tool we use every day to solve problems and make decisions. Furthermore, the teacher can mention that the ability to compose and decompose numbers is an important foundation for learning more advanced mathematical concepts, such as multiplication and division.

The teacher should conclude the lesson by reinforcing the idea that mathematics can be fun and interesting, and that with practice and effort, all students can become good mathematicians. They should encourage students to continue exploring and learning about the fascinating world of mathematics.