Nine-year compulsory education Six-year primary school mathematics Volume IV Page 33.

Teaching purpose:

1. Let students further deepen their understanding of numbers within ten thousand and master the comparison methods of numbers within ten thousand.

2. Let students experience the close relationship between mathematics and daily life.

3. Cultivate students' ability of knowledge transfer and abstract generalization.

Teaching focus:

Master the method of comparing the size of numbers within 10 thousand.

Teaching difficulties:

Proficient in comparing numbers.

Teaching process:

First, pave the way for migration.

(Projection shows) On the beautiful beach, there are two turtles arguing. They all say they are old (show two turtles with numbers written on their backs: 8 and 13). One is 8 years old and the other is 13 years old. Please help them compare which little turtle is bigger. How can we express the relationship between them? (8 < 13) How to compare their sizes? (One digit is 965.

The next four digits are very happy. Guess, if the number you just dialed is not three digits, but the ratio of five digits to four digits, can four digits win? Why?

2. Feedback exercise (gesture judgment: Yes, extend the thumb and forefinger of the right hand)

765○2456 100 1○999 123○96

(1) Introduce thinking: What do you want to say after seeing these exercises? (Students think and discuss, are enthusiastic, speak boldly and express their opinions. )

(2) Teachers grasp the temperature and inspire thinking: what should be compared first to compare the numbers?

3. Summary: Comparing the size of numbers, the number with more digits is larger and the number with less digits is smaller.

[Description: Use students as small referees, and compare the sizes of different digits, so that students are all in high spirits and eager to try. According to the law of knowledge transfer, how to compare numbers with different digits is deduced by comparing the numbers within 100, which fully cultivates students' innovative spirit and tastes the joy of success. ]

(3) Teaching examples 1 1(2)

1. The first challenge, three numbers and four numbers, four numbers won by their own numbers. The second game is about to start, with four digits of 5640,8790. (Written on the blackboard) Now these two numbers are all four digits. Who is older and who is younger? (5640 < 8790) Judge XX, why do you think 8790 is big? (5640 has five thousand, 8790 has eight thousand, and five thousand is smaller than eight thousand, so 5640 < 8790) This referee is good!

2. Feedback exercises.

4532○3279 1999○6007698○703

What did you learn from the second round of the Tour and the feedback exercise?

3. Summary: The same digit is greater than the highest digit.

(4) Teaching examples 1 1(3)

Everyone wants to compete in the kingdom of length numbers, and the competition is getting more and more fierce. In order to reward the players, the king specially sent two trucks of soda [show 1 1(3) car map]. One truck brought 3864 bottles (blackboard books) and the other (3529 bottles) (blackboard books). Which car has more soda? Ask a classmate to say. (above 3864 and below 3529)

If you agree with him, please raise your hand. With so many people supporting you, can you tell me why you think 3864 is big?

(The students were startled, and they immediately threw themselves into thinking. Few people raised their hands. )

Guide the students to discuss in groups of four and send representatives to speak. (It's all the same at the top, just 100,800 is greater than 500, so 3864 > 352). Who wants to talk?

After watching the game, you can sum up your experience and talk about the same number, and the highest number is the same. How to compare?

2. Now, can you line up all the guests in a four-digit family (showing four digits in the new time chart) in descending order? ( 1230