Objectives (5 - 7 minutes)

1. Develop students' ability to identify problem situations involving addition and subtraction in everyday contexts, encouraging them to think logically and analytically.

2. Provide students with the opportunity to apply addition and subtraction skills in practical activities. This will help reinforce mathematical concepts and enhance their problem-solving skills.

3. Encourage collaboration and communication among students, promoting an active and engaged learning environment. This will be done through group activities, where students will have to discuss and solve problems together.

Introduction (10 - 15 minutes)

1. Recalling previous concepts: The teacher will start the lesson by reminding students of the basic concepts of addition and subtraction that were previously learned. This will be done through simple questions and quick games, such as "How many fingers do you have on one hand? If we take one away, how many are left?" or "If you have 3 apples and give one to your friend, how many apples do you have now?".

2. Contextualized problem situation: The teacher will then present two problem situations that are relevant to the students' daily lives. For example: "This morning, at school, we had 10 pencils in the box. During class, we used 4 of them. How many pencils are still in the box?" or "At snack time, we had 7 cookies. If each student ate one cookie, how many cookies are left?".

3. Capturing students' attention: The teacher will explain that knowing how to add and subtract is very important in various daily situations, such as when they are playing and need to count the game pieces, or at snack time when they want to divide equally among friends. He may also mention how these skills are used by adults in things like counting money or shopping.

4. Introduction of the topic: The teacher will then introduce the topic of the lesson. He will explain that they will learn to solve addition and subtraction problems in a more formal way, but will also continue to use these skills in practical situations. To engage the students, the teacher may tell a short story about how he used addition and subtraction in a real situation, such as solving a math problem or baking a cake.

Development (20 - 25 minutes)

The teacher will have the option to choose from three practical activities to develop the concepts of addition and subtraction with the students. The activities are divided into three levels of difficulty, but the teacher can adapt them according to the class's needs.

Activity 1: "The Apple Basket" (Easy)

1. The teacher will propose the following situation: "Imagine we have a basket of apples. At first, it is empty. Let's add some apples, one at a time, until the basket is full. Then, let's remove some apples from the basket, one at a time, until it is empty again."

2. The teacher will use concrete objects (such as plastic fruit pieces) to represent the basket and the apples, and students will be encouraged to make the corresponding additions and subtractions. The teacher may ask questions like: "How many apples do we have in the basket now? If we remove one, how many apples will we have?"

Activity 2: "Addition Bingo" (Medium)

1. The teacher will prepare bingo cards with numbers from 1 to 20. He can do this before the lesson or ask students to help.

2. The teacher will then draw two numbers from a bag without the students seeing. The students will have to add the drawn numbers and cover the result on their bingo card. The first student to cover all numbers in a line, column, or diagonal will be the winner.

Activity 3: "The Great Car Race" (Difficult)

1. The teacher will create a race track on the classroom floor using tape. He will draw several numbered spaces along the track.

2. Each space will represent a mathematical operation. For example, space 5 could be an addition (2+3=), space 8 could be a subtraction (10-2=), and so on.

3. The students will be divided into teams and, one at a time, will have to solve the mathematical operation on the space where their team's car is.

The teacher will have the freedom to choose one of the above activities to implement in the classroom, taking into account the level of difficulty and the class's concentration ability. During the activities, the teacher should circulate around the room, assisting students as needed and encouraging collaboration and mutual respect.

Feedback (10 - 15 minutes)

1. Group Discussion: The teacher will gather all students and promote a group discussion about the solutions found by each team. He will encourage students to share their answers and the methods they used to reach them. The teacher will ask questions like "How did you solve this problem?" and "Why do you think this is the correct answer?". This moment allows students to have a deeper understanding of the concepts of addition and subtraction, while learning from their peers' strategies.

2. Reflection on Learning: After the group discussion, the teacher will propose that students reflect for a minute on what they learned in the lesson. He will ask two simple questions to guide students' reflection: "What was easiest for you in today's lesson?" and "What was the most difficult?". Students can express their reflections through words or drawings, depending on their writing skills.

3. Connection between Theory and Practice: To conclude the lesson, the teacher will explain how the practical activities they carried out connect with mathematical theory. He will review the concepts of addition and subtraction, emphasizing how they were applied in the problem situations of the lesson. The teacher may also suggest that students think of other daily situations where they can use addition and subtraction.

4. Teacher's Feedback: The teacher will provide feedback to the students, praising their efforts in solving problems and highlighting the effective strategies they used. He may also point out areas where students can improve, without making negative criticisms. The goal is to encourage students to continue learning and striving.

5. Lesson Closure: The teacher will end the lesson by thanking everyone for their participation and effort. He will reinforce that everyone is learning and that it is normal to have difficulties at certain times. The teacher may also suggest extra activities for home, such as solving addition and subtraction problems in an activity book or online games.