Objectives (5 - 7 minutes)

1. Familiarize students with the concept of angles and their characteristics.
2. Teach students to identify and classify angles by their opening, that is, whether they are right, acute, or obtuse angles.
3. Provide students with the opportunity to apply what they have learned by classifying angles in everyday situations.

Secondary objectives:

• Stimulate logical reasoning and students' observation skills.
• Promote interaction and collaboration among students through group activities.
• Develop students' communication skills, allowing them to express their ideas and solutions clearly and coherently.

Introduction (10 - 12 minutes)

1. Reviewing Content: The teacher starts the lesson by reviewing with students the concepts of straight lines, curved lines, right angles, obtuse angles, and acute angles. They can use drawings on the board or real objects in the classroom to illustrate these concepts visually and tangibly.

2. Problem Situations: The teacher presents two problem situations to the students:

   2.1. "Have you noticed that pencil tips have different shapes? Some are very sharp, others more rounded. What do you think this has to do with our math class?"

   2.2. "And when you look at the clock, how do you know what time it is? How are the numbers arranged on the clock face? Does this have to do with angles?"

3. Contextualization: The teacher explains that understanding angles is very important because they are present in our daily lives, in objects, constructions, nature, time, music, and many other things.

   They can give examples like:

   • "Who here has heard of a rock band called 'Angle 180'?" (Fun fact: The right angle is exactly 90 degrees, which is half of a complete angle, which is 180 degrees. The band's name refers to this.)

   • "And when you play soccer, have you noticed that the field is a rectangle? The angles formed on the field are all equal to 90 degrees, that is, they are right angles."

4. Capturing Students' Attention: To spark students' interest, the teacher can propose a challenge. They show a piece of paper and ask, "Do you think you can fold this piece of paper and form a right angle with it?" They then give the students some time to try to solve the challenge.

   (Tip for the teacher: To fold the piece of paper and form a right angle, students need to fold it in a way that the ends meet exactly in the middle of the paper.)

Development (20 - 25 minutes)

Activity 1: Exploring Angles with the Body

1. The teacher organizes students into small groups and asks them to form a circle on the floor with the help of their peers. The teacher can mark a large circle on the floor with adhesive tape or use cones to delimit the circle.

2. Next, the teacher instructs students to position themselves in different ways inside the circle, forming angles with their arms or legs. For example, the teacher can ask students to form right, acute, and obtuse angles with their bodies.

3. The teacher circulates among the groups, assisting and correcting when necessary. They can ask students to explain the type of angle they formed.

4. At the end of the activity, the teacher gathers all students in a circle to share their discoveries. Each group is invited to demonstrate an angle they formed and say whether it is a right, acute, or obtuse angle. The teacher reinforces correct observations and makes necessary corrections.

Activity 2: Measuring Angles with the Protractor

1. The teacher hands a protractor and large sheets of paper to each group of students.

2. They instruct students to draw different angles (right, acute, and obtuse) on the sheets of paper and then use the protractor to measure the drawn angles.

3. The teacher circulates among the groups, assisting students in measuring the angles and clarifying any doubts that may arise.

4. After students have measured the angles, the teacher gathers everyone in a circle to share their discoveries. Each group is invited to show an angle they drew and measured, and state the obtained measurement. The teacher reinforces correct observations and makes necessary corrections.

Activity 3: Angle Game

1. The teacher organizes students into small groups and hands each group a set of cards with different angles drawn (right, acute, and obtuse).

2. Students must then classify the cards into piles according to the type of angle they represent.

3. The teacher circulates among the groups, assisting and correcting when necessary. They can ask students to explain why they classified the cards in that way.

4. At the end of the activity, the teacher gathers all students in a circle to share their discoveries. Each group is invited to show a card and say in which pile it was placed and why. The teacher reinforces correct observations and makes necessary corrections.

(Tip for the teacher: All these activities can be adapted as needed for the class. The important thing is that students have the opportunity to explore and experiment with angles in a practical and fun way.)

Return (10 - 15 minutes)

1. Group Discussion: The teacher gathers all students in a large circle for a group discussion. They ask each group to share their discoveries and solutions from the activities carried out. This allows students to see different ways to approach the same problem and encourages the exchange of ideas and collaboration among them.

   • The teacher can start by asking: "What angles were you able to form with your body in the first activity? And in the second activity, what angles did you draw and measure? And in the angle game, how did you decide to classify the cards?"

   • They can also ask students to explain how they reached certain conclusions. For example: "Why do you think this angle is obtuse? Why is this angle acute? How did you measure this angle? Why did you choose to classify this card as a right angle?"

2. Connection to Theory: After the discussion, the teacher makes the connection between practical activities and theory. They reinforce the concepts of right, acute, and obtuse angles, and how they can be formed and measured.

   • They can ask: "After everything we have seen and done today, how can we define a right angle? And an acute angle? And an obtuse angle? How can we measure an angle?"

   • They can also recall the problem situations presented at the beginning of the lesson and ask: "So, now that we know more about angles, what do you think the different tips of pencils have to do with angles? And how are the numbers arranged on the clock face?"

3. Final Reflection: To conclude the lesson, the teacher proposes a moment of individual reflection. They ask two simple questions and ask students to think for a moment before responding.

   • Question 1: "What was the most interesting thing you learned about angles today and why?"

   • Question 2: "How can you use what you learned today about angles in everyday situations?"

   • The teacher can give a minute for students to think about the answers and then ask some volunteers to share their reflections with the class.

4. Teacher's Assessment: During the group discussion, the teacher carefully observes students' contributions, responses to their questions, and presented reflections. This gives them valuable feedback on students' understanding of the lesson content and helps guide the next lesson, if necessary.

   • Additionally, the teacher can take this opportunity to correct any misconceptions that may have arisen during the activities, reinforcing the correct concepts and clarifying any remaining doubts.

(Tip for the teacher: Throughout the return, it is important for the teacher to create a welcoming and respectful environment where all students feel comfortable sharing their ideas and opinions. They should praise the effort and participation of everyone and avoid any kind of criticism or judgment. The goal is to promote active learning, self-confidence, and a love for learning in students.)

Conclusion (5 - 8 minutes)

1. Lesson Summary: The teacher begins the conclusion by summarizing the main points covered in the lesson. They reinforce the definition of angles and their classifications by opening, briefly explaining what right angles (90 degrees), acute angles (less than 90 degrees), and obtuse angles (more than 90 degrees) are. They also emphasize the importance of angles in our daily lives, mentioning examples such as the arrangement of numbers on a clock and the shape of pencil tips.

2. Connecting Theory with Practice: The teacher then connects theory with practice, recalling the activities carried out. They highlight how students were able to explore and experiment with angles in a practical way and how they could apply theory in practice, whether by forming angles with the body, measuring angles with the protractor, or classifying angles in the angle game.

3. Extra Materials: To deepen students' understanding of the subject, the teacher suggests some extra materials. For example:

   • Recommend children's books that address the topic of angles in a playful and fun way, such as "The Boy Who Learned to See" by Ruth Rocha and Otávio Roth.

   • Suggest educational websites with games and interactive activities about angles, such as "Khan Academy Kids" and "Educativos Alpha".

   • Propose that students observe angles around them at home, at school, and in other places, and try to identify and classify these angles.

4. Importance of the Subject: Finally, the teacher emphasizes the importance of the subject for students' daily lives. They explain that understanding angles is useful in many situations, from building constructions and interpreting maps, to solving mathematical problems and appreciating works of art. Additionally, they remind students that knowledge about angles can be applied in other areas of the curriculum, such as science, geography, and arts.

   • The teacher can conclude the lesson by saying: "Remember, math is everywhere, even in the angles we see around us. So, keep observing, exploring, and learning. See you in the next lesson!"

(Tip for the teacher: During the conclusion, the teacher should use simple and accessible language, avoiding technical terms and mathematical jargon that may confuse students. Above all, they should convey enthusiasm and passion for the subject, showing students that math can be fun and interesting.)