First, create situations and introduce teaching.

Dialogue: Do students like reading extracurricular books? Teachers like it, too Now please follow the teacher to the library.

Show me the photos.

Question: What do you see from the projection?

(* * * There are 224 books and 2 bookshelves, each with 4 floors).

Second, deepen and explore new knowledge at different levels.

1, dialogue: We have found so much information, can we ask a step-by-step calculation question? (Answer immediately) What other questions can you ask about one-step calculation?

What other questions can you ask, such as two-step calculation? How many books are there on each shelf? If the students can't figure it out, the teacher can figure it out)

Narrator: Can you solve this problem? You can try it in your notebook. If you find it difficult, you can discuss it with your deskmate. Maybe you will have unexpected gains.

After you finish, talk to your deskmate and tell me what you think.

Say the answer and write it on the blackboard:

Method1:224 ÷ 2 =112 (Ben) Method 2: 2×4=8 (layer)

1 12÷4=28 (Ben) 224÷8=28 (Ben)

What does 224÷2= 1 12 mean? What does "224" mean? What about "2"? What do you want? So what's the name of the company? What's the significance of 1 12÷4=28?

What does 2×4=8 mean? What does "2" mean? How about "4"? What does 2×4 require? So what's the name of the company? What does 224÷8=28 mean?

2. Distinguish the similarities and differences between the two methods and reveal the theme.

Dialogue: Compared with the first two questions, what are the characteristics of the third question? How many conditions are needed? How many steps are there to solve the problem?

The teacher gave the meaning of continuous division of application problems and wrote down the topic on the blackboard: solving practical problems with two-step calculation.

Students are very clever and can solve problems in different ways. Let's have a look. What are the similarities and differences between these two methods?

Difference: (1) The first step is different. The first method, step one, put several books on each shelf on average; The first step of the second method is to find out how many layers there are in two bookshelves.

(2) The calculation method used in the first step is different. The first method uses division in the first step; The second method uses multiplication in the first step.

(3) The names of the units in the first step are also different. The first method, two companies with the same name, are both "Ben"; In the first step of the second method, the company name is "layer".

Similarity: The second step uses division. You can find out how many books are put on each shelf on average.

Third, try to apply and practice consolidation.

1, complete the "Want to Do" question 1.

Talk: In the third grade, we added a subject called science. In order to make it easier for students to understand some scientific knowledge, the teacher decided to take everyone to visit the Science and Technology Museum. Look at that.

Show the scene diagram of the question 1 and guide the students to observe and collect information: What information can you know from the picture? How many known conditions have you found? What's the problem? (Imagine 1 14 people in your mind, and divide them into two teams on average, and each team is divided into three groups on average.)

Then let the students do it independently. (first board performance) (small blackboard or projection can be used)

Share your own algorithm at the same table, first talk about what you are, and then talk about what you are.

Report by name, comment collectively and talk about solving problems. What is the first step? According to which two known conditions? )

2. Complete the second question "Think about it and do it".

Dialogue: There is a third-grade child Xiaoming, whose grandfather is ill. The doctor gave him a bottle of medicine. Listen. Grandpa asked Xiao Ming, how long can this bottle of medicine last?

Show the pictures of the second question, and guide the students to observe and collect information: What information can you know from the pictures? How many known conditions have you found? What's the problem?

Name the conditions and problems of this problem and describe them completely.

Discuss the meaning of this information at the same table, discuss the solution to the problem, and talk about what you plan to calculate first, then calculate.

Report by name, comment collectively and talk about solving problems. (first board performance) (small blackboard or projection can be used)

3. Complete the third question "Think about it and do it".

Narrator: On weekends, Xiaoming and Xiaogang want to buy table tennis bats. Please help him figure out how much each ping-pong bat costs.

Show the scene diagram of question 3, and guide students to observe and collect information: What information can you know from the picture? How many known conditions have you found? What's the problem? (hint has hidden conditions: there are 2 children. )

Name the conditions and problems of this problem and describe them completely.

Share your algorithm with your deskmate. Say what you plan to calculate first, and then say what you plan to calculate.

Report by name, comment collectively and talk about solving problems. (first board performance) (small blackboard or projection can be used)

4. (Maneuver) Complete the fifth question "Think about it and do it".

Narrator: The students are so clever that even Xiaoyan can't help coming to our classroom. But they also bring a problem. Look at that.

Show the scene diagram of question 5, and guide students to observe and collect information: What information can you know from the picture? How many known conditions have you found? What's the problem?

Name the conditions and problems of this problem and describe them completely.

Share your algorithm with your deskmate. Say what you plan to calculate first, and then say what you plan to calculate.

Report by name, comment collectively and talk about solving problems.