Objectives (5 - 7 minutes)

1. Identify decimal numbers: Students will be able to recognize and identify decimal numbers, understanding the relationship between the whole part and the decimal part of a number.

2. Perform additions and subtractions with decimal numbers: Students should be able to add and subtract decimal numbers, applying the concepts learned correctly and efficiently.

3. Solve problems with everyday situations: Students will be encouraged to apply the concepts of adding and subtracting decimal numbers in real-life situations, stimulating problem-solving and connection with everyday life.

Introduction (10 - 15 minutes)

1. Review of Decimal Numbers: The teacher will start the lesson by reviewing the basic concepts of decimal numbers, explaining that they are used to represent parts of a whole. Using examples from everyday life, such as money (e.g. $1.50) or measurements (e.g. 1.5 meters), the teacher will help students understand the importance and relevance of decimal numbers.

2. Problem Situation 1: The Bike Ride: The teacher proposes a situation where a student is riding his bike from home to school. He rides 1.5 km to get to school and then rides another 3.25 km to reach a park. The teacher will ask the students: 'How many kilometers in total did the student ride on his bike?'. This question will introduce the addition of decimal numbers in a contextualized way.

3. Problem Situation 2: The Candy Store: The teacher presents another situation where a student has a candy store. He sold 1.75 kg of candies and then sold another 0.5 kg of chocolates. The teacher will ask: 'How many kilograms of sweets did the student sell in total?'. This question will introduce the subtraction of decimal numbers in a contextualized way.

4. Contextualization of the Importance of the Subject: The teacher will explain that adding and subtracting decimal numbers are essential skills for dealing with money, measurements, and other everyday situations. He will emphasize that by mastering these skills, students will be able to solve daily problems more easily and accurately.

5. Introduction to the Topic: Finally, the teacher will introduce the topic of the lesson, explaining that students will learn to add and subtract decimal numbers in a practical and fun way. He will reassure the students, saying that just as they learned to add and subtract whole numbers, they will also be able to perform these operations with decimal numbers. The teacher will also highlight that by the end of the lesson, students will be able to solve the proposed problems efficiently and correctly.

Development (15 - 20 minutes)

The teacher will present three practical activities for the students, each focused on a specific concept: recognizing decimal numbers, adding decimal numbers, and subtracting decimal numbers. These activities are designed to be fun and engaging, encouraging students to apply what they have learned in a practical way. The teacher can choose to do all three activities or choose the one that is most appropriate for the class.

Activity 1: 'The Sunken Treasure'

1. The teacher will prepare a basin with water and some floating objects (Styrofoam balls, bottle caps, etc.).

2. On each object, the teacher will stick a decimal number. For example, on a Styrofoam ball, the number 1.35 can be glued, and on a bottle cap, the number 0.75.

3. Divided into groups, students will have to 'dive' (using their hand, not their mouth!) and retrieve an object from the basin without looking at the decimal number on it.

4. Once all objects have been retrieved, each group will have to add up the decimal numbers they found. Then, the results will be shared with the class, and the teacher will check which group found the correct sum.

Activity 2: 'The Students' Race'

1. The teacher will draw a finish line on the classroom floor.

2. Students, divided into groups, will have to draw the decimal numbers (with the whole part already established by the teacher) that represent the distances in meters between the starting line and the finish line. For example, in one group the number can be 2.3 and in another 4.8.

3. Each group will have to calculate the difference between the distance they drew and the distance from the starting line to the finish line.

4. The group whose calculation is closest to the correct answer will win the 'Students' Race'.

Activity 3: 'The Candy Store'

1. The teacher will 'set up' a candy store in the classroom, with various candies of different weights (M&M's, candies, etc.) and their respective prices.

2. Divided into groups, students will be 'customers' of the candy store. They will have to choose different candies and calculate the total price of their choices.

3. The group that reaches the total price closest to the actual value will receive a sample of the candies they chose!

Each activity is a problem situation that requires the use of skills in adding and subtracting decimal numbers. By participating in the activities, students will be applying the concepts in a practical and fun way, consolidating learning effectively.

Return (10 - 15 minutes)

1. Group Discussion (5 - 7 minutes): The teacher will gather all students in a large discussion circle. Each group will have the opportunity to share their solutions and strategies for the activities. The teacher will encourage students to explain how they arrived at their answers, highlighting the most efficient and creative strategies. During the discussion, the teacher will ask questions to stimulate students' reflection and check the group's overall understanding. For example: 'Why did you decide to add/subtract these numbers first?' or 'What would you do differently if you had to repeat the activity?'.

2. Connection with Theory (2 - 3 minutes): After the discussion, the teacher will reinforce the theoretical concepts that were applied in the activities. He will take the opportunity to highlight the similarities and differences between the strategies of the different groups, emphasizing that there are several correct ways to solve a mathematical problem. The teacher will also review the basic steps for adding and subtracting decimal numbers, showing how students used these steps in their solutions.

3. Individual Reflection (3 - 5 minutes): To end the lesson, the teacher will propose that students reflect on what they have learned. He will ask two simple questions to guide students' reflection:

   • 'What did you find most interesting about adding and subtracting decimal numbers?'
   • 'How can you use what you learned today in everyday situations?'

   Students will have a silent moment to think about the answers. Then, the teacher will give the opportunity for those who want to share their reflections with the class.

4. Teacher's Feedback (1 minute): To conclude, the teacher will give general feedback on the lesson, praising the students' efforts and reinforcing the main points that were learned. He will also emphasize the importance of continuous practice for the improvement of math skills.

This return is a crucial part of the lesson plan, as it allows the teacher to assess students' understanding, consolidate the acquired knowledge, and encourage reflection and critical thinking. Additionally, it provides students with the opportunity to express their opinions and learn from each other, promoting a collaborative and positive learning environment.

Conclusion (5 - 7 minutes)

1. Lesson Summary (2 - 3 minutes): The teacher will recap the main points covered during the lesson. He will highlight that students learned to identify decimal numbers, perform additions and subtractions with decimal numbers, and solve everyday problems involving these operations. The teacher will summarize the basic steps for adding and subtracting decimal numbers, reinforcing that these are very similar to the steps used for adding and subtracting whole numbers.

2. Connecting Theory with Practice (1 - 2 minutes): The teacher will explain how the lesson connected theory with practice. He will emphasize that by doing the practical activities, students were able to apply theoretical concepts in a concrete and contextualized way. Additionally, the teacher will stress that the group discussion and individual reflection allowed students to connect their practical actions with theory, facilitating understanding and retention of concepts.

3. Extra Materials (1 minute): The teacher will suggest extra materials for students who wish to deepen their knowledge on the subject. These may include textbooks, online math games, educational videos, and interactive math apps. The teacher may also recommend that students practice adding and subtracting decimal numbers at home, using money, measurements, or other everyday examples.

4. Importance of the Subject (1 minute): Finally, the teacher will reinforce the importance of adding and subtracting decimal numbers in everyday life. He will explain that these skills are essential for dealing with money, measurements, and other practical aspects of everyday life. Additionally, the teacher will highlight that by mastering these skills, students will be able to solve problems more efficiently and accurately, which is a highly valued skill in various areas of life and work.

The conclusion is a crucial moment to consolidate learning and motivate students to continue exploring the subject on their own. By reinforcing the main points of the lesson, connecting theory with practice, and emphasizing the importance of the subject, the teacher will help students understand and value what they have learned.