People's education publishing house, the first volume of first grade mathematics, 73~75 pages.

Teaching objectives:

1. Through reading picture books, telling stories and other activities, help students understand ancient counting methods and generate learning needs. Preliminary experience of decimal system.

2. Let students know "10" through the activity of "swinging the stick"? One is? 1 10 ",master? 1 1~20 composition,? Learn more about the decimal system.

3. Through the game of "Find a home for numbers", help students accumulate experience in mathematics activities and get a preliminary understanding of numbers.

4. Help students set up "1 1" activities. The concepts of "unit" and "ten bits" further feel the value of bits.

Teaching emphases and difficulties:

You know? 1 1~20, okay? 10 which one is it? 1 10, sense bit value.

Teaching preparation:

Courseware, picture books, sticks, cards, counters, etc.

Teaching process:

Read picture books first, tell stories, and learn about ancient counting methods.

1. Read the picture book and understand the story.

Teacher: Every student has a picture book story, which is a small gift from Teacher Ni. Its name is the ancient count. Have you all seen it? ? One of us? Get up and remember. Please look at the big screen.

Courseware shows the picture book and plays the audio of the picture book "Ancient Numbers".

According to the story in the picture book, the teacher improvised the courseware and began to ask questions.

Teacher: Yes, what's the matter? ? You got it?

Health: Did the second child change the 10 small stone? 1 big stone.

Teacher: You mean this? 1 The big stone actually represents several small stones.

Health:? 10.

Teacher: Plus the outside, how much did the second child hit?

Health:? 14.

2. Taste the picture book and feel the origin of "counting by ten".

Teacher: Keep watching.

Courseware shows picture books:

Teacher: Why does the second child have this idea?

Health: She thought of it with her hands. (Raise his little hand when he speaks)

Teacher: How cute! Why don't you show us your little hands? How many fingers do we have?

Health:? 10.

Teacher: You see, 10 is in our hands, so the wise ancients thought of replacing the small stone of 10 with a big one.

Second, put sticks, build relationships and learn composition.

1. Pendulum? 12, establish decimal relation.

(1) Ask questions.

Teacher: This is the story of ancient people counting. I think the ancient people's experience in counting must be helpful to our study. Let's count them together today.

Teacher: There are some sticks on each student's desk. Please count how many sticks you have.

Health:? 12.

Teacher: I really didn't realize this was 12 without telling me? Root, can you think of a way to let others see that it is 12 stick quickly? Show it quickly.

(2) student operation.

(3) material selection.

Teacher: The students thought many ways, and Teacher Ni also collected some. Let's have a look.

Show students how to pose. 1 1 grounding rod

Health: I am 1 with a space in the middle.

Teacher: Oh, he is 1 and the number is 1.

Teacher: How do you count it?

Show the students how to swing ②: Put two sticks on the ground.

Health: I'll count two.

Teacher: What about this one?

Show the students how to pose ③: 5, 5, 2.

Health: Mine is 5+5+2= 10.

Teacher: You count to five and five.

Teacher: Oh, what does 12 mean? What about yours? Do students understand?

Show the students how to swing ④: 10 plus 2.

Health: Is he A? A pile of 10, with two beside it, means 12.

Teacher: Did you find out? ? No matter how we put it, how many sticks are there on each small white board?

Health:? 12.

Teacher: There are only 1 1 pendulums, 2 pendulums and 5 pendulums. A classmate has 10 pendulums and several pendulums. Who do you admire more?

Teacher: Many students have chosen No.4, so let's look at No.4 first.

Teacher: How many do you think there are in this pile?

Health:? 10.

Teacher: Let's count. It's really 10 great. Just now he put 10 sticks in a pile for convenience. Can you play this? 10 sticks are tied into a bundle like this, and then combined with two sticks, it is 12. Is this fast?

Teacher: Starting from today, we have a new agreement: Is that enough? 10 and then we bundle them into one? Bundle, when we bundle, how much must it be?

Health:? 10.

Teacher: What's the sum of the two outside?

Health:? 12。

Teacher: Can you arrange your sticks like this so that others can quickly see that they are 12?

Teacher: Let's count 10 together like this and tie it into a bundle with rubber bands. Let's see 12.

(4) Verify the conjecture.

Teacher: Is this really fast? ? Let's verify it. (show? 14) How much?

Health:? 14。

Teacher: plus 1, how much is it?

Health:? 15。

Teacher: What about 1?

Health:? 16。

Teacher: How about another 1? It seems that this is really fast!

Teacher: Just now, some students said that two pendulums are also very fast. Let's have a look. 14) Can you read it quickly? How much is this?

Health:? 12。

Teacher: Don't worry, let's count. 14。

Teacher: What do you think of 2? Root? 2? How about the number of roots? ? Or is it more convenient to use our new agreement?

Health: It is more convenient to use the new agreement.

Teacher: It seems that 10 sticks really have its advantages.

2. Put a stick and learn to shape.

Teacher: Teacher Ni also tidied up some. Is it okay? See how much this costs?

(1) courseware demonstration:

Teacher: How many sticks are these?

Health:? 13.

Teacher: How do you know?

Health:? The bundle of 1 is 10, and there are three others outside, making a total of 13.

(2) Show courseware:

Teacher: How much are these?

Health:? 17.

Teacher: Let's count. A stick has seven sticks. Not really. How do you know this bundle is 17?

Health: Because we have a new agreement. This? 1? Is it tied? 10.

Teacher: OK, remember our agreement.

(3) Teacher: Then let's recall the counting process just now.

Teacher: 1 branch means 1 piece,1piece means1piece. What did we do with these 10 sticks today?

Health: Tie it into a bundle.

Teacher: With this burden, they become a family? Well, how many ones are there in 1 ten?

Health:? 10.

Teacher: So we say 10 one? 1 tenth, 1? Ten is 10 one.

(4) Teacher: Increase the difficulty and see what it is. ? Say it? Reason.

Courseware demonstration:

Health: It's 20. Because there are two 10, it is 20.

(5) Teacher: Today, we quickly saw these figures of ten yuan and twenty yuan. Who do you think helped us?

Health: Sticks and rubber bands.

Teacher: yes, with rubber bands, we will soon put? 10? It is more convenient to tie sticks into a bundle.

Teacher: (Summary) Today we are at 10? On the basis of study? 1 1~20, we have a new agreement. Do you remember?

Teacher: Let's relax and play a little game.

Teacher: There is a straight line on the blackboard. There are many friends living on this line. Look, who's here?

Health:? 10。

Teacher: Teacher Ni sent 10 home. Who is this?

Health: 20.

Teacher: I went back to his home at 20.

Teacher: Some students got a digital card from their teacher. Tell your deskmate who you are. Please go to the front 1 1~ 19.

Teacher: Introduce yourself to everyone.

Teacher: The rest of the students will be little commanders. One? Get up and help them find a home.

Student activities, for? 1 1~ 19 looking for a house.

The teacher's instruction is: Where is 15? 18? 15 neighbors go home quickly! A few friends who are more than 10 and less than 14 hurry home; Last few friends, hurry home!

Camera question: Is 18 closer to 20? Or closer to 15?

Teacher: Let's read it together!

10? 1 1? 12? 13? 14? 15? 16? 17? 18? 19? 20

Third, distinguish "1 1", construct digits and feel the value of digits.

Teacher: Children, our story continues, remember? ? Smart ancients can 1 big stones and? 1? What does a small stone mean? 1 1, can you also express it with a stick? Out? 1 1 But here comes the question, now there is only? 2? Can a small bead of the same color and size as this one still be displayed? 1 1?

Students don't agree, some people think so, some people? If you don't think so, please come to the front to discuss and talk about your own ideas.

Health 1: (I don't think so) I think two beads can only represent two, so even two can't represent it? 1 1。

Health 2: (I think so) I think 1 bead can be regarded as 10, and the other bead as 1. Isn't that enough?

Health 3: (I don't think so) But are these two beads the same size? ? Not a big one and a small one.

Teacher: Yes, they all look the same. How do you let everyone know who is 10 and who is 1?

Health: Just write 10 on one bead and 1 on the other.

Teacher: Do you want to hear what Teacher Ni thinks?

Teacher: Actually, his idea just now is very similar to that of our mathematicians. Mathematicians made a counting tool (display counter) for us. You got it?

Health: abacus.

Teacher: This is called a counter. Mathematicians helped us invent this. Look, there are many places on the counter. Starting from the right, the first one is called "unit" and the second one is called? "ten"

Teacher: With the help of the counter, can you express 1 1? Let's have a look.

Teacher: Draw a counter on the blackboard and put it in a position? 1 little bead, what do you mean?

Health:? 1 one.

Teacher: Put it in ten places? 1 little bead, isn't it? 1 one!

Health: What's this? 1 ten digits.

Teacher: Great. 1 10 and 1 10 add up to 1 1.

2. Call "1 1".

Did the teacher dial? 1 1, students continue to dial? 12~20。

Teacher: Can you dial the number on the counter?

Teacher: (Summary) We not only know these figures, but also express them with the help of counters.

Fourth, contact life and continue to write picture books.

Teacher: Today we know the number 1 1~20, remember? ? Let's start with the story of ancient people counting. But the story is not over yet. ...

Teacher: If you continue to draw and talk, what kind of pictures will you use to express your understanding of these numbers?

Teacher: Teacher Ni also brought pictures drawn by children in Beijing. Do you want to see it? Can you understand their thoughts? ? I will leave this task to you. Teacher Ni is looking forward to it. ...