Teaching objectives:
1. You know, multiplying 0 by any number will get 0.
2. Understand that 0 is multiplied by any number to get 0, and can be calculated correctly.
3. Cultivate students to use mathematical thinking to solve practical problems.
Teaching focus:
Mastering 0 multiplied by any number will get the conclusion of 0.
Teaching difficulties:
A preliminary understanding of the truth that 0 is multiplied by any number to get 0.
Teaching methods:
Guiding inquiry method, stimulating interest method and problem transfer method.
Teaching preparation:
multimedia courseware
Teaching process:
First, review the import (multimedia demonstration) (rushing to answer)
9+0= 100+0= 256-0= 872-0= 3407-0= 8255+0=
Teacher: The students are really amazing. How can you work out such a big number so quickly? Did you find any patterns?
Health1:"0" and any number are added to get the original number.
Health 2: Any number minus "0" equals the original number.
Teacher: On this basis, this class will continue to learn the calculation of multiplying multiple digits by one digit.
(revealing the topic, about the multiplication of 0)
Second, create a situation
Teacher: Do students like little monkeys? In this class, the teacher invited some greedy little monkeys to the class. Who can tell me what you found? (The courseware shows the scene picture on page 66 of the textbook.)
Teacher: (Name the students and tell the information in the picture)
Teacher: According to the information in the picture, who wants to make up a story about mathematics for everyone? Name the students, look at the pictures and tell stories according to the information.
Teacher: It's wonderful. The students listened so carefully that they must like the story very much. According to this story, what math problems can you ask?
Teacher: Students think independently, and then ask questions by name.
How many peaches are there in the seven plates? )
Third, the new interactive award.
1. Teaching Example 4
Show the courseware (How many peaches are there in one of the seven plates? )
What method have you thought of to solve this problem? Can it be expressed by an equation?
Health 1: addition calculation: 0+0+0+0 = 0 (pieces)
Teacher: Why do you calculate like this? Why do 7 zeros add up to 0?
Health: Because 0 doesn't mean anything.
Teacher: How else can I work out this formula?
Student 2: Multiplication calculation: 0×7=0 (pieces), that is, how many are seven zeros.
Teacher: That's good. This is a method to solve the multiplication problem of 0. Students should never forget to write an answer after listing the formulas.
2. Think about it, what are 0× 3, 9× 0 and 0× 0 respectively? Why? (Courseware demonstration)
(1) Students complete the calculation independently.
(2) report the calculation results by roll call and talk about your own calculation ideas.
Teacher: Who will talk about the first question and tell the teacher what you think?
Health: 0×3 means the sum of three zeros, which is 0.
Teacher: That's good. Who can say that again?
Health: 0×3 means the sum of three zeros, which is 0.
Teacher: Do other students think so?
Health: Yes.
Teacher: Discuss at the same table according to the teacher's method. How do you view the second and third questions respectively?
(Talking at the same table and reporting)
Health: 9×0 means the sum of nine zeros, which is 0.
Teacher: Boys and girls, let's see if what he said is right (show the courseware).
Student: Yes.
Teacher: Who can repeat that?
Health: 9×0 means the sum of nine zeros, which is 0.
Teacher: What does 0×0 mean?
Health: 0×0 means none, or 0.
Teacher: Students, do you think the same as him?
Health: The same.
Teacher: (showing the courseware) The students are so clever that they think the same way as the little angel.
3. Question: Please observe the above formula carefully and communicate in groups. What do you find from the formula? (communication report)
Health 1: The above formulas are all multiplication formulas.
Health 2: The above multiplication formulas are all 0 times a number.
Health 3: The products of the above multiplication formulas are all 0.
Teacher's summary: What do you find by observing the above formula and the law of summary?
Health: I found that multiplying 0 by any number gets 0.
We have learned new knowledge, and now the teacher will test you and finish the first question on page 66 of the book. (Show the courseware after the students finish) (Call the students to answer)
Teacher: Have you finished?
Health: I'm done.
Teacher: Now the teacher will test everyone (show the courseware). Each student says a group.
How do you solve individual problems? ( 0×6 5+0 )
Teacher: Since students can work out the result, now the teacher wants students to observe it through the above formula (discussion: Is the result of multiplying a number by 0 the same as that of adding a number to 0? Why? We can discuss it at the same table.
Student: No, the result of multiplying 0 by a number is still 0, and the result of adding 0 to a number is still this number.
Fourth, consolidate and expand.
1. Complete the second question of "doing" on page 66 of the textbook.
2. Courseware demonstration: How many flowers are inserted in the vase?
Choose a happy one.
4. Can you tell the results of the following two formulas quickly?
1+2+3+4+5+6+7+8+9+0
1×2×3×4×5×6×7×8×9×0
(Because the second one has 0, you get 0 after multiplication, and you get 0. )
(emphasize that "0" is multiplied by any number to get 0)
Verb (abbreviation of verb) course summary
Teacher: Through today's study. What have you learned? (Name the students to sum up the answers)
Sixth, blackboard design