Teaching content: Simple arrangement and combination of Unit 8 in the first volume of the second grade of compulsory education curriculum standard experimental textbook (People's Education Edition).

Teaching objectives:

Through observation, experiments and other activities, students find out the number of the simplest things to arrange and combine, and initially experience the exploration process of the simple arrangement and combination law.

Make students learn simple permutation and combination methods and exercise their observation, analysis and reasoning abilities.

Cultivate students' consciousness of thinking about problems in an orderly and comprehensive way.

Feel the close connection between mathematics and life and stimulate students' interest in learning mathematics.

Teaching emphasis: experience the exploration process of simple arrangement and combination law.

Teaching difficulty: understanding the difference between simple things arrangement and combination.

Teaching aid preparation: courseware

School tools preparation: two people at the same table have a digital card (1, 2, 3), and each person has a piece of exercise paper and a pencil box.

Teaching process:

Introduce the situation first and start teaching.

Teacher: "Little friend, today we are going to learn' Wide Angle of Mathematics'. (Showing the courseware) First, let's go to the Math Castle! However, the door is locked with a combination lock. Do you want to unlock the password to play? "

Health: Yes!

The doorman said: The password is a two-digit number consisting of 1 and 2. (Please read all)

Teacher: What number do you think it might be?

Health: 12 or 2 1. (blackboard writing)

Teacher: "Could it be 1 or 2?"

Health: Impossible.

Teacher: "Why?"

Student: The question requires two digits, and 1 or 2 is a number.

Teacher: What are the "two digits"?

Health: Ten and one.

Teacher: 1 or 2 is impossible. Can you determine which is the password, 12 or 2 1?

Health: No.

The doorman added: The password is the smaller of 1 and 2. (Please read all)

Health: 12!

Teacher: Boy, you are so clever!

Second, put a few activities to experience new knowledge.

(1) Teacher: There is a question in the math castle: How many different two-digit numbers can 1, 2,3 make up? Give students some time to think. ) Next, let's study this problem at the same table. Please listen carefully to the requirements before you start work.

(Courseware demonstration) Requirements: Use three digital cards in the envelope, and two people at the same table will cooperate. One person has a number, and the other person writes the number on the exercise paper. Finally, count one * * * and set several two digits.

Students work together at the same table to explore, teachers patrol, and purposefully write representative articles on the blackboard.

Feedback: 1, (omitted)

2. (Write more)

3, (messy handwriting)

4, 12, 2 1, 13, 3 1, 23, 32 * * 6-Can it be expressed by an expression?

Teacher: What do you think of her writing? (Health: General)-Switch the two numbers.

5, 12, 13, 2 1, 23, 3 1, 32 * * * 6-Can it be expressed in an expression?

Teacher: What do you think of her writing? (health: positive)-from childhood 1, 2, 3 rounds were relegated to the tenth place.

Teachers' organizations analyze them one by one: which child wrote this? Can you two deskmates talk about your ideas?

(Write in order, ask the students to say several times: "Who understands their ideas? Why didn't you say it again? " I really don't know. You can ask the students to put it on the platform. Shake hands and praise the students who answered well. )

Teacher: After reading so many methods, which one do you think is better? Why? (General) If you use 1, 2, 3, 4 to form several different two-digit numbers, which method do you think can be used to write quickly and well? (type 5)

(2) Teacher: Just now, the teacher shook hands with a child and shook hands with a child. So, (courseware shows) how many times do three people shake hands every two people like this?

Student: 2, 3, 6 times ...

Teacher: How many times?

To solve this problem, we can (write on the blackboard: perform). Please find the children around you to perform.

Students report several times and choose a group to perform. After the performance, write on the blackboard (3 times)

Teacher: If we are at home, there are no three people, or during the exam, how do you shake hands? Do you have any other good ideas? (Drawing and Display)

Let the students draw a picture and show the feedback.

(3) Compare and understand the difference between arrangement and combination.

Teacher: Through the study just now, let's think about such a question: (courseware demonstration)

Why can three numbers add up to six double digits, but three people can only shake hands three times?

Teacher's summary: There is a sequence of pendulum numbers.

How many double digits can 0, 2 and 3 make up?

Teacher: Can you write these figures quickly? Write them down on the exercise paper.

Feedback-Teacher: Why did it become four? Which two are missing? Why? (0 cannot be written in the highest digit)

Third, life mathematics, consolidate exercises.

Teacher: Actually, there are many such problems in life. Let's go out of the castle and see life!

1, (courseware demonstration)

Teacher: There are also math problems with the matching of clothes. Two clothes and two pants. How many ways can you match them?

Health: 4 kinds.

Teacher: How to match it?

The students said that the teacher demonstrated the courseware.

Teacher: Can you list a formula? (2×2=4)

2. (Courseware demonstration)

Teacher: Table tennis also has math problems. Every two athletes play a game, how many games should they play against each other?

Health: 3 games.

Teacher: What kind of questions do you think are similar to those in this class?

Health: handshake problem.

3. (Courseware demonstration)

Teacher: There are also math problems in the process of paying for things. How do I pay this fifty cents?

Ask individual students to answer, and the teacher writes on the blackboard:

① 5 angle

②2+2+ 1=5 (angle)

③ 2+1+1+1= 5 (angle)

(4)1+1+1+1= 5 (angle)

Teacher: In what order did the teacher write it?

Health: First take 5 horns, then take 2 horns, and finally take all as 1 horn.

Fourth, sum up this lesson, review the old and learn the new.

(Courseware demonstration)

Teacher: After listening to this lesson, what did you gain?

What do you want to say to everyone?

(The number of rows is sequential. )