Talk: See what the teacher has. (Triangle), can you find out how many angles it has?

Second, organize activities to explore new knowledge.

1. Cognitive perspective

Projection display: project the pictures in the textbook.

Talk: Look, what corners are there in the picture? (Student answers)

Follow-up: Corners are everywhere in our lives. How many vertices does an angle have? How many sides? Can you find the angle from the surface of some objects around us? When found, point out their vertices and edges.

Fold a corner

Dialogue: We already know the corner. Can we bend a corner with dexterous little hands? See who folds fast and well. (Fold the corners with prepared white paper)

3. Angle comparison

(1) Question: Can you make your folding angle bigger? What do you do? Can you make it smaller? How did you do that?

(2) When the hour hand and the minute hand on the clock face rotate, they form different angles. Can the students compare which angle is bigger? What method is used to compare?

(3) Talk: Observe the two triangles in the teacher's hand (a big triangle and a small triangle are made of two pieces of paper), which triangle is bigger? Still the same size? Do you know what the size of the horn is related to?

Third, solid application, expansion and extension

1. Textbook exercises 1. Dialogue: The clever little monkey found some numbers. He wants to test the children. Dare to accept its challenge? Projection display graphics: which are corners and which are not? Angular. Can you point out its vertices and edges? Answer by roll call.

2. Practice the second question in the textbook. Dialogue: The curious kitten thinks that the children are learning well, so she comes to consult us. Show it by projection. Every picture has several corners. Tell it to your deskmate.

3. Exercise 3 and 5 in the textbook. Dialogue: the clever rabbit saw that everyone's skills were so good, and finally he couldn't help but test us and project the questions. Discuss at the same table and communicate in class.

4. Exercise 4 in the textbook. Talk: Teacher Goat was very satisfied with everyone and decided to take the children to play.

Pull and close the scissors. Tell me about the angle change you saw.

Fourth, the class summarizes and assigns homework.

Dialogue: What did you learn from this lesson? Go home and show your parents what you learned today, and find out which things in your house have horns.

Comments:

1. Guide students to be good at discovering teaching problems from daily life and activating life experience.

Let students fully experience and understand mathematical knowledge and apply it to practical activities. Through "finding corners in common objects in life", students feel that mathematics is closely related to life, enhance their understanding of the value and function of mathematics, and stimulate their enthusiasm for learning mathematics.

2. Guide students to explore independently and promote mathematical thinking.

Pay attention to guiding students to practice, understand knowledge in operation and develop thinking. Change the situation in which teachers dominate the classroom, boldly let go, change the past of simply watching teachers demonstrate, let students do it themselves, and mobilize students' initiative. This lesson designs the links of "finding", "speaking" and "doing" to help students understand the angle and perception angle in mathematics activities, make students more interested in learning, and effectively cultivate their observation ability, operation ability, expression ability and analysis and generalization ability.