Objectives (5 - 7 minutes)

1. Understand the concept of length and the need to measure objects in mathematics.
2. Identify and compare different lengths of everyday objects.
3. Develop measurement skills using non-standard units of measurement (e.g. palms, steps, pens).

To achieve these objectives, the teacher will use a practical and playful approach, involving students in measurement, comparison, and discussion activities. The goal is for students to internalize these mathematical concepts in a fun and meaningful way.

Introduction (10 - 12 minutes)

1. Reviewing Content: The teacher starts the lesson by reviewing with students the concept of geometric shapes, especially squares and rectangles. He can show some examples of objects that students know and that have these shapes, such as the window, the blackboard, the tables, etc. The teacher can also review the difference between 2D and 3D shapes.

2. Problem Situations: The teacher then presents two problem situations that will arouse students' curiosity and introduce the importance of measuring lengths. For example:

   • "Have you noticed that there are different sizes of boards in the classroom? How can we know which is the largest and which is the smallest without touching them?"
   • "How many steps do you think are needed to cross the classroom from one side to the other? And to cross the school corridor?"

3. Contextualization: Next, the teacher contextualizes the importance of measuring lengths in students' daily lives. He can mention simple situations, such as choosing a book in the library based on its size, or the need to measure the distance to cross a street safely.

4. Introducing the Topic: To introduce the topic in a fun way, the teacher can propose two challenges:

   • "Challenge 1: How many hand spans are needed to measure a classmate's height?"
   • "Challenge 2: How many steps are needed to measure the length of the classroom?"

These challenges will set the stage for the practical activity that will follow, where students will have the opportunity to measure and compare lengths in a concrete and playful way.

Development (20 - 25 minutes)

During this stage, students will be invited to participate in practical activities involving the measurement of lengths and size comparison. The teacher can choose one or more activities, depending on the available time and the dynamics of the class. The proposed activities are:

1. Measuring with Feet: The teacher distributes pairs of socks to each group of students and marks a starting point. The students, one at a time, then put their foot in the sock, remove it, and place it back in front of the sock. This is repeated until they reach the other side of the room. They count how many times they had to do this, and the teacher records it on the board. The teacher can then ask how many "feet" are needed to cross the room. This activity helps students understand the concept of length and compare different lengths in a playful way.

2. Measuring with Steps: This activity is similar to the previous one, but instead of using socks, students take steps to cross the room. The teacher marks the location of the first step, and the students take steps until they reach the other side of the room. The number of steps required is counted and compared with the number of steps taken by classmates. This activity helps students understand that different people have different step lengths and that measurements can vary.

3. Measuring with a Ruler: The teacher divides the room into groups of 4 or 5 students and gives each group a ruler. The students are instructed to measure the length of different objects in the classroom, such as the blackboard, the table, the book, etc. They record their measurements and share them with the class. The teacher reinforces the importance of measuring from the same starting point to the end to obtain an accurate measurement. This activity helps students understand how to use a ruler to measure lengths and compare different measurements.

Throughout all activities, the teacher should move around the room, asking questions to guide students' understanding and correct any errors. It is important for the teacher to emphasize that there are no right or wrong answers in these activities, as the goal is to develop the ability to measure and compare sizes in a playful and meaningful way.

Feedback (10 - 15 minutes)

1. Group Discussion: The teacher gathers all students and promotes a group discussion about the solutions found by each team. He can start by asking each group what they measured and how they did it. Then, the teacher can ask students to share their findings and observations. For example, if students measured the length of the room, they may notice that the measurements varied slightly from group to group, which is an opportunity to discuss the importance of accurate and consistent measurement.

2. Connection to Theory: Next, the teacher should connect the practical activities carried out with the theory. He can ask students how they believe the activity of measuring with feet or steps relates to length measurement in mathematics. The teacher can explain that in mathematics, we use standardized units of measurement, such as centimeters and meters, but in everyday situations, we can use non-standard units of measurement, such as feet or steps, to make estimates.

3. Final Reflection: To conclude the lesson, the teacher proposes that students reflect for a minute on what they have learned. He can ask two simple questions to guide this reflection:

   • "How can the measurement and size comparison activities we did today help us in everyday situations?"
   • "What did you find most interesting in today's lesson?"

4. Teacher's Feedback: The teacher then gives brief feedback on the students' performance, praising their efforts and highlighting the skills they demonstrated during the activities. He can also suggest ways for students to continue practicing these skills at home, such as measuring the length of objects in different rooms of the house, for example.

5. Lesson Closure: Finally, the teacher concludes the lesson by reinforcing the importance of measuring and comparing sizes in mathematics and in everyday life. He can say, for example, that understanding lengths helps in activities such as building a block tower, organizing books on a shelf, or even choosing the size of clothing to buy.

Remembering that the estimated time for this stage may vary depending on the class's pace and the number of groups formed. The important thing is that all students have the opportunity to share their discoveries and reflections, and that the lesson ends in a positive and productive way.

Conclusion (5 - 7 minutes)

1. Content Review: The teacher begins the conclusion of the lesson by reviewing the main points covered during the lesson. He can do this interactively, asking students to share what they remember about the importance of measuring and comparing lengths, and how they did this during the practical activities. The teacher can also briefly review the concepts of length, geometric shapes, and units of measurement, ensuring that students have a clear understanding of these concepts before ending the lesson.

2. Connection between Theory and Practice: The teacher then explains how the lesson connected theory and practice. He can mention that during the activities, students had the opportunity to apply theoretical concepts of length and measurement in a concrete way. Additionally, the teacher can highlight that the practical activities allowed students to see mathematics in action, making it more relevant and meaningful to them.

3. Extra Materials: To deepen students' understanding of the lesson topic, the teacher can suggest some extra materials for home study. For example, he can recommend math books for children that include sections on measurement and size comparison. The teacher can also suggest online educational games that involve practicing measuring and comparing sizes. Additionally, the teacher can propose that students engage in practical activities at home, such as measuring the length of objects in different rooms of the house or making length estimates using body parts or non-standard objects.

4. Subject Importance: Finally, the teacher concludes the lesson by emphasizing the importance of the subject for students' daily lives. He can mention that the ability to measure and compare sizes is useful in many everyday situations, such as cooking (e.g. measuring ingredients), building (e.g. marking the length of a shelf), and even playing (e.g. assembling a puzzle). The teacher can also highlight that mathematics is a powerful tool for understanding and exploring the world around us, and that the skills learned in today's lesson are just the beginning of a journey of continuous discovery and learning.

With this conclusion, the teacher ends the lesson clearly, reinforcing the main points learned and motivating students to continue exploring the fascinating world of mathematics.