Understanding of quadrilaterals

1. Teaching objectives:

1. Intuitively perceive quadrilaterals, understand the characteristics of quadrilaterals, be able to distinguish and identify quadrilaterals, further understand rectangles and squares, and know that their angles are all right angles.

2. Cultivate students’ ability to observe, compare and generalize through activities such as guessing, searching, talking, circling, and drawing.

3. Through pictures and things in life, students can feel that quadrilaterals are everywhere in life, and cultivate students' awareness of applying mathematical knowledge to life.

2. Important and difficult points in teaching:

Be able to intuitively perceive quadrilaterals, use their characteristics to correctly distinguish and identify quadrilaterals, and further master the characteristics of rectangles and squares.

3. Teaching tools:

Slides, worksheets, rectangles, squares.

4. Teaching process:

(1) Create situations and introduce excitement.

Various graphics form a beautiful world, adding infinite colors to our lives. Children, please look at the big screen (show the pictures). There are all kinds of graphics in these pictures. Are they beautiful? (Student: beautiful) There are many quadrilaterals hidden in these patterns we admire. Who would like to guess what the quadrilaterals might look like? The students’ imaginations are so rich and they speak so well. In this class, the teacher will accompany the students into the world of graphics to explore the mystery of quadrilaterals.

Teacher’s writing on the blackboard: understanding of quadrilaterals (students read the topic together)

(2) Initial perception and discovery of characteristics.

1. Circle and draw the quadrilateral in the study sheet.

(Production of courseware) Teacher: There are 14 figures here. Please use the study sheets in your hands to circle the figures you think are quadrilaterals, and then communicate with your friends to see if you have the same idea. ?.

(Students draw circles by hand, teacher inspects).

Reporting and communication: Tell me how many shapes you circled? (Answer by name, other students can add answers)

Teacher: So is what you circled correct? Let's verify it together. Please look at the big screen. (The courseware demonstrates how to circle the quadrilaterals) Have you circled everything correctly? Don't worry if you are wrong, you will understand why you made the wrong circle in our next study.

2. Discuss the characteristics of quadrilaterals.

Teacher: Now we divide these shapes into two categories, the quadrilaterals into one category, and the other shapes into one category, and then ask students to observe these quadrilaterals, what do you find about them*** Same characteristics? If you find something, share it with your deskmate about what you found.

(Students observe, think and communicate)

3. Group communication.

Teacher: Who wants to tell you what you discovered? What are the different characteristics of these quadrilaterals?

The teacher wrote on the blackboard: It has four straight sides and four corners.

Emphasis: the four sides must be connected end to end.

Summary: A quadrilateral is a figure surrounded by four line segments.

Teacher: Well done, kids! The teacher admires your spirit of discovery and thinking. The teacher wants to test whether your little eyes can distinguish between true and false. Are you afraid? (Student: Not afraid)

4. (Production of courseware) Analysis: Observe the following graphics. If it is a quadrilateral, put " " in ( ), if it is not a quadrilateral, put " " in ( )

5. Find the quadrilateral in life.

Teacher: Children, you have mastered the characteristics of quadrilaterals, can you find which objects in our lives have quadrilateral surfaces?

(Students speak freely).

6. Draw a quadrilateral.

Teacher: Children, the teacher wants to give you a thumbs up again. You have used your eyes to find so many quadrilaterals around us. Can you draw this wonderful shape? Ask students to use a ruler and pen to draw two quadrilaterals with different shapes in the idea map on the worksheet.

? (Students draw quadrilaterals by hand, teacher inspects).

(3) Independent exploration, characteristics of long and square shapes.

Pick out rectangles and squares from the quadrilaterals drawn by students and ask: The quadrilaterals drawn by this student are the ( ) and ( ) we have known before. Rectangles and squares are special quadrilaterals. Do you know them? What's so special about it?

1. Independent exploration.

Teacher: Then ask the students to take out the rectangles and squares in the school tools, compare their angles with the angles of the triangle, and measure their sides with a ruler. You can also use folding Compare their sides and see what you can discover? (Students perform hands-on operations, teachers inspect)

2. Report and exchange, courseware demonstration, the demonstration introduces the names of the sides of rectangles and squares.

3. Discussion: The connection and difference between rectangle and square.

The similarities are: both rectangles and squares have four right angles.

The difference is: the opposite sides of a rectangle are equal, and the four sides of a square are equal.

4. Draw long and square shapes on graph paper.

Teacher: Children, through the exploration just now, we have a deeper understanding of rectangles and squares, so can you still draw them with your skillful hands? Please draw a rectangle and a square in the grid on the worksheet.

(Students draw rectangles and squares on graph paper, and the teacher inspects and provides guidance).

(4) Consolidate practice and improve abilities.

Teacher: Children, your willingness to learn, think, and be serious and down-to-earth in your studies have deeply infected me. Teacher believes that you have gained a lot today, right? Do you dare to accept my examination of you?

1. Fill in the blanks.

A quadrilateral has ( ) angles and ( ) right-angled sides.

The rectangle has 4 ( ) angles, and its ( ) angles are equal.

A square has ( ) angles ( ), and its ( ) angles are equal.

? 2. Paint.

? Requirements: Paint the rectangle red, the square yellow, and the other quadrilaterals green. (Production of courseware) Students tell the number they painted.

? 3. The envelope contains a quadrilateral. Guess what shape it might be.

(5) Summary of the whole lesson and organization of knowledge.

What did you gain from this class? (Students answer freely)

Teacher: In this lesson we learned about quadrilaterals and discovered the characteristics of rectangles and squares. In the next lesson we will apply this knowledge to solve practical problems.