1, learn the methods and steps of drawing angles with protractor;

2, will use a protractor to draw an angle of a specified degree;

3. Learn to draw special angles with a pair of triangles;

4. Experience the process of drawing an angle with a protractor, learn to express and exchange your views in exploration, learn to cooperate with others, and form a learning experience.

Teaching focus

Learn the methods and steps of drawing angles with protractor.

Teaching difficulties

Learn to draw angles with a protractor.

Teaching preparation

Physical projection, PPT courseware, protractor, triangle board, etc.

teaching process

First, basic exercises.

(Courseware demonstration) Oral calculation:

12×6= 25×3= 180×4= 15×6= 180-45= 60÷4= 36×2= 29×2= 17×5= 96÷6=

Design intention: Oral calculation is an essential skill in mathematics learning. Improving oral arithmetic ability is not a one-time process, but a long-term training process. Therefore, before each class, we should carry out warm-up training of oral arithmetic to achieve the degree that practice makes perfect. Using courseware to demonstrate oral arithmetic can not only improve classroom efficiency, but also quickly focus students' attention on learning.

Second, introduce new courses.

Can students draw a five-pointed star?

(Courseware demonstration)

Two basic mathematical characteristics of a standard pentagram and a pentagram;

① The five line segments are equal in length;

② Each vertex angle is 36 degrees. ...

Now how do you think you can draw a standard five-pointed star?

If you can draw an angle of 36 degrees, this problem will be solved easily.

(writing on the blackboard: drawing corners)

Design intention: In order to stimulate students' interest and arouse their enthusiasm for participation, draw a standard five-pointed star as a topic of great interest to students to introduce new lessons. According to the two mathematical characteristics of the five-pointed star, each side is equal in length and each vertex angle is 36 degrees. I instruct students to draw an angle of 36 degrees, and further explore how to draw an angle with a specified degree.

Third, explore the method of drawing corners.

1, swing angle.

Please draw an angle of about 36 degrees on the paper with a stick.

Guess it's close? How are you going to test it? (Show students' 36-degree angle with the help of physical projection)

(triangle, protractor, etc. )

It seems that to draw an accurate angle, we should not only use visual inspection, but also use drawing tools such as triangle and protractor.

2. Try to draw a corner.

Try to draw a 36-degree angle with the tool according to the 36-degree angle you set.

3. How to draw an angle in communication?

(Show and communicate with the help of physical projection. )

4. Try to draw an angle of 60 degrees and 105 degrees.

Multimedia shows the process of drawing corners. )

5. How to draw some angles with special degrees?

Students exchange painting methods.

Design intention: The premise of drawing an accurate angle is the general appearance of an angle in your mind. Therefore, before discussing the drawing method of an angle, let students do a series of activities, such as setting the angle, estimating the angle and distinguishing the angle, so as to achieve the effect of accurately drawing the specified angle. The use of advanced teaching equipment, such as physical projection, fully demonstrates the students' thinking method and operation process, which is intuitive, vivid, accurate and convenient, and greatly improves the efficiency of classroom teaching.

Fourth, consolidate practice.

1, paper folding angle (90 degrees, 45 degrees, 135 degrees, etc. ).)

After folding, ask the students: How many degrees can you fold?

2, (multimedia display) spelling: spell with triangles, say what special degrees of angles can be spelled and how to spell.

Verb (short for verb) Homework:

Draw a standard five-pointed star with the angle drawing method learned today.

Design intention: at the end of the class, let the students draw a standard five-pointed star, which can be said to echo from beginning to end and apply what they have learned.