Opening remarks: Dear judges and teachers, hello everyone!I am candidate No. 5 for the interview of a primary school mathematics teacher, and the topic of my trial lecture today is "Two digits multiplied by two digits (carrying)", so I will start my trial lecture below.
1. Import. Teacher: Hello students, please take a seat.
Teacher: Students, autumn is here, Peppa Pig's family is going on an outing on the weekend, let's see where they go, shall we?
Teacher: Wow!It's a forest, but during the outing, Mother Pig asked a question: there are 37 rows of trees in this forest, and there are 48 trees in each rowThis stumped Paige, classmates, can you help her?
Teacher: I see that you are also frowning, it's okay, come with the teacher to ** "Two Digits by Two Digits (Carry)", and see if you can help her solve this problem with the knowledge you have learned today
2. New awards. Teacher: Then who will tell me how to set the columns?Teacher: You are sitting upright, so please tell me.
Teacher: Well, what he said is 37x48=, your thinking is very quick, we can also write it as 48x37=Teacher: Can anyone estimate it first and see how many trees there are?Teacher: Your hand is raised highest, you say.
Teacher: Oh, he said about 2,000 trees, what do you think?
Teacher: Well, 48 50, 37 40, 50x40 = 2000, so it's about 2000 trees, so should it be greater than 2000 or less than?For less than 2,000 trees, your idea is truly unique.
Teacher: However, we often need specific data in our daily life, so can you use the knowledge we have learned to calculate it concretely?Let's discuss it in small groups of four.
Teacher: I see that everyone has discussed about the same, who will tell me how your group calculates?Teacher: I see you can't wait, so let's talk about it.
Teacher: He said that they divided 37 into 30 and 7, then multiplied them by 48, and then added the numbers together, and the Xi result was 1776 trees.
Teacher: Is there a different way?
Teacher: I see that the hands of this group are like small trees, so please send a representative from your group. Teacher: Well, he said that you can calculate it vertically, but how do you calculate it?You come to the teacher to write.
Division: 48x37, the single digits and the ten digits should be aligned separately, and then what?Who's going to come first?
Teacher: Yes, you have to count the single digit first, 8x7=56, so where should this 56 be written?
Teacher: Oh?He said to align 6 and 7 and 5 and 3. Going on, 4x7=21, 1 is aligned with the multiplication sign, and 2 is in front of 1. Huh?Some students have found a problem, and this is only half of the calculation, which is bigger than the 2000 mentioned before, which is definitely not right.
Teacher: It seems that everyone is really sharp-eyed. Is this classmate a little bit of a problem, please take a seat, who can help him find out what the problem is, teacher: It is to use 8x7=56 first, 6 to write on the single position, 5 to move forward. 7x4=28, plus the previous 5, should be 33, which is 336.
Teacher: Remember, 5 in 56 means 5 tens, and 28 here means 28 tens, and when you add them up, you get 33 tens.
Teacher: Multiply the second multiplier by the 3 on the tens of digits to multiply the first multiplier, and finally add them together to get 1776. Teacher: You have a very clear mind and a very careful observation, do you understand?Teacher: Do you understand?
Teacher: Then, when we do problems in the future, if we encounter the problem of multiplying two digits by two digits and need to carry the digits, we must remember to carry the digits, and in the process of pen calculation, we must remember to add the number that comes up.
Teacher: Is that helping Peppa Pig solve the problem of the mother pig?
Teacher: Finally, let's summarize the calculation method of multiplier is a two-digit number: when the column is vertical, align the same digits, first multiply the first factor by the unit of the second factor, and align the last digit of the number with the unit of the first factor;Then multiply the first factor by the unit of the second factor, and the last digit of the number is aligned with the ten digit of the first factorFinally, add the product of the two multiplications.
Teacher: What we should pay attention to is that when calculating, whoever is on the top of the dozens will go up to the previous one.
Division: Let's test it again through a few Xi questions to see if you really have mastered it. 3. Consolidation.
Teacher: Do you dare to accept my challenge?Come, let's look at the Xi on the big screen, count vertically, and see who does it quickly and correctly.
Teacher: I see that my classmates have put down the pen in their hands, and I must have finished it, so I asked my classmates to show them the answers he wrote
Teacher: Well, it's all the same, it seems that everyone has a very good grasp of the knowledge of this lesson!
Fourth, summary. Teacher: Happy times are always short-lived, and before you know it, it's time for class to end again. Think back to what we have gained today
Teacher: I heard some students say that they know how to multiply two digits by two digits: when the column is vertical, align the same digits, first multiply the first factor by the unit of the second factor, and align the last digit of the number with the unit of the first factorThen multiply the first factor by the unit of the second factor, and the last digit of the number is aligned with the ten digit of the first factorFinally, add the product of the two multiplications.
Teacher: The student who made the mistake just now said that next time he must remember to carry and add the number of rounds. It's great, and correcting your mistakes is the biggest improvement!
Teacher: It seems that everyone has listened carefully to this class and has a very good grasp of the knowledge of this class.
5. Homework. Teacher: The Xi of mathematics should not be limited to the classroom, but after class, the teacher will leave some small tasks for everyone, and everyone will do the homework problems in the homework book, and then share your gains today with your parents.
Teacher: Okay, that's all for this class, goodbye students!
Dear teachers, the above is all the content of my trial lecture, can I erase the board book?