Teaching objectives:
1. Knowledge and skills: Make students contact the meaning of addition and subtraction with their own life experience, explore and understand the quantitative relationship in the simple practical question "What is the number more (less) than a number", and can use addition and subtraction to answer correctly.
2. Process and method: In the process of solving problems, students can further understand the meaning of addition and subtraction, cultivate their basic thinking ability, initially learn to reflect on the rationality of answers according to the meaning of questions, and constantly accumulate experience in solving simple practical problems.
3. Emotion, attitude and values: let students feel the close connection between mathematics and real life, experience the fun of cooperation and communication with classmates, and enhance their confidence in learning mathematics well.
Teaching emphasis: explore and understand the quantitative relationship in the simple practical question "What is the number that is more (less) than a number", and use addition and subtraction to answer correctly.
Difficulties in teaching: Exploring and understanding the quantitative relationship in the simple practical question "What is the number more (less) than a number?"
Teaching preparation: self-made courseware, 33 magnetic flowers, several flowers for students, etc.
Teaching process:
First, review the old knowledge and pave the way for the new lesson.
1. Do children like playing games? Today, let's play a game of catching flowers. Teacher, here is a bunch of flowers. Only one is allowed to catch, to see who catches more. (Please catch it by two students)
2. Teacher: Guess who caught more? (Students casually say the result of the guess)
Teacher: Who has more and how much? Just line up the flowers.
Teacher: First, line up the girls' flowers (for girls) and stick them on the blackboard: ooo … ooo.
Teacher: Notice how the teacher arranges the boys' flowers ...? Cardboard sticker: OO…O
Health: One faces the other.
Teacher: What's the use of such a pendulum facing each other? (See at a glance who is more and who is less) Yes, this one.
So we can say that girls catch more than boys. How many? On the other hand, men.
There are fewer students than girls. One less?
3. Expose the topic: In this lesson, we will learn a simple practical problem: find a number that is more (less) than a number. (Sticker theme)
Yesterday Sunday, Xiaoying and her good friend Obana Xiaoping also played a flower catching game! Let's take a look at their results!
Second, explore new knowledge and teaching examples.
1, show the sample scene (courseware show: click on the information of three people posing flowers).
2. Guide the students to say what you know. Ask the students to answer and write down on the blackboard:
Xiaoying: There are 1 1 flowers.
Xiaohua: Three more than Xiaoying.
Xiaoping: Three less than Xiaoying.
3. After reading these materials, can you ask some math questions?
(1) Guide students to ask questions: ① How many small flowers should be put? (2) How many Xiaoping?
(2) Let's look at the first question:
According to Xiaohua, we can arrange the flowers in a row, and then we can know how many flowers Xiaohua wants to put. Do you want to have a try? Thinking about how to put it, it is obvious that Xiaohua has three more places than Xiaoying. Tip: Below the first row, one is facing the other. (Open the small box of learning tools)
② Students type out boxes of primary school furniture and operate them.
(3) Tell me how you put it? The students replied that the teacher was acting on the blackboard.
-"Question: Why put 1 1 flower first?
-"Thinking: When there are as many rows in the second row as in the first row, why put three more rows?
-"Feedback: How many flowers have we put in? How to calculate in the form of columns? Blackboard: 1 1+3 = 14 (sheets)
-"Discussion: Is the calculated figure the same as the presented result? Why use 1 1 plus 3, 1 1? What does 3 mean? Does the score exceed 1 1? (Guide the students to substitute the calculated numbers into the conditions and reflect on the rationality of the answers. )
4. Transition: Naming Student: Now who will tell us how many flowers Xiaohua has put in?
(1) How much is Xiaoping? Can you put it on yourself first, and then calculate how many Xiaoping put it on?
(2) Students begin to operate, calculate and fill in books P33.
(3) Discussion: What are the first emissions? How to place the second row, so that it can be clearly seen that Xiaoping is three places less than Xiaoying? Why use subtraction? What does 1 1 mean? What does 3 mean? Is the calculation result the same as that of Hua Pian? Answer by roll call.
5. Teacher's summary: We calculated the number of flowers to be put by Kobanawa Xiaoping by putting them first and counting them later. After working out the answer, we have to see whether the result meets the condition of "greater than (less than)" according to the known conditions.
Third, guide the completion of "thinking and doing".
1, do the "do it if you want" question 1.
(1) Look at the picture and say what the known conditions are and what the required questions are. And talk about it completely, (2) student column answers. If some students have difficulties, they can use learning tools to set them first and then list them. )
(3) Feedback: Talk about formulas and answers.
(4) Guided reflection: Will the score be less than 32 squares? Why?
Step 2 consider doing 2
(1) Students answer independently, name formulas and answer sentences.
(2) Guided reflection: Will you get more than 36 pots?
3. Think about doing 3.
(1) Students answer independently, name formulas and answer sentences.
(2) Transition: Students learn so well that teachers can't help applauding you. Please listen:
Step 4 clap your hands
The teacher took three pictures, and the teacher said, can you take two more pictures than me? (Name shooting)
The teacher took five pictures, and the teacher said, can you take two less pictures than me? (Name shooting)
The teacher took four shots, and the teacher said, can you take two more shots than me? (shoot together)
Fourth, classroom extension.
Teacher: I didn't expect math knowledge to be used in relaxed games! Teacher, here are some interesting topics. Do you want to challenge them? .
1. According to the diagram: □□□□□□□□□□□□□□□□
○○○……
(1) Teacher: There is a ... after the O here. Do you know what this means? Let me give you an example first! Teacher's demonstration: ○ 2 is less than □, ○ How much? (Name Answer: 9-2 = 7 (pieces)
(2) Anyone can make a condition for everyone to come up with.
2. Is it interesting? Xiaoying and Obana Xiaoping want to test everyone when they see that they are doing well in their studies.
(Courseware demonstration: Conditions: Xiaoying puts 15 flowers, Xiaohua puts less flowers than Xiaoying, and Xiaoping puts more flowers than Xiaoying.
(requirement: put it in your head before discussing it:)
(1) Who has more flowers in Obana?
(2) Who poses the most and who poses the least among them?
(3) How many small flowers may have been put? what do you think?
(4) How many can Xiaoping pose? what do you think?
3. Do you still want to challenge? Think about it. Do you know how many black rabbits there are?
There were 30 (1) white rabbits, and 10 black rabbits were more than gray rabbits. How many black rabbits are there?
(2) There are 30 white rabbits, 20 fewer than black rabbits. How many black rabbits are there?
Students think independently. what do you think?
Conclusion: What do you want to tell everyone through these two questions? When we calculate a simple practical problem, we should look at the topic carefully, and we should not look at it more and add more, but look at it less and subtract less. )
Verb (abbreviation of verb) course summary
What did you gain from this class? Use the skills learned today to solve some problems in life. I believe you will become smarter and smarter!
Six, class assignments:
Complete "Think and Do" question 4 in the math exercise book.
Seven, blackboard design: