The manuscript of "Continuous Addition and Subtraction" 1 says that it is fertile soil to correctly grasp the intention of the textbook and understand the spirit of the new curriculum standard, so the educational concept that is updated at any time and the solid theoretical foundation are the endless springs. Only a steady stream of "clear spring" irrigates fertile "soil" can make the land present a vibrant scene.
First of all, talk about textbooks and students.
The lesson of "continuous addition and subtraction" comes from the first volume of compulsory education curriculum standard experimental textbook, page 72.
The knowledge of addition and subtraction is often used to solve problems in our daily life. After learning the addition and subtraction of two numbers within 10, on the one hand, it expands the meaning of addition and subtraction, on the other hand, it also embodies the concept that "everyone can get the necessary mathematics" proposed by the new curriculum standard. This is also a difficult content in this unit. Mainly in the calculation process, it is difficult to calculate the results in two steps, especially in the second step, the number calculated in the first step needs to be added and subtracted to complete the calculation task. Moreover, the thinking method of this knowledge point is very helpful for learning addition within 20, so the position of this knowledge point in the textbook is more important.
Students have been familiar with the meaning of addition and subtraction before learning this knowledge, and they have also mastered the number addition and subtraction within 10. Moreover, students have the life experience of "adding, adding" and "dividing, dividing again", so it is not difficult to understand the meaning of increasing and decreasing. However, the first-grade children are limited by age characteristics, and their attention is easily distracted, and their intentional attention time is short, and their thinking is still in the stage of concrete image thinking. Knowledge points that need strong attention, such as continuous addition and subtraction, are difficult for them to learn, which is manifested in the phenomenon that the second step of calculation is blocked because they cannot see or forget the result of the first step.
Second, talk about teaching philosophy.
1, mathematical culture view. Mathematics is a kind of culture, which is not only a kind of achievement, but also a witness to the development of human civilization. Therefore, students should experience the process of knowledge formation in teaching and pay attention to their experiences and experiences.
2. Constructivist psychological theory: Mathematics learning is a positive construction process. On the basis of existing knowledge and experience, students must make new mathematics learning materials interact with the original cognitive structure and actively construct a new mathematical cognitive structure.
Third, talk about teaching objectives.
1, knowledge goal: know the meaning of addition and subtraction and the order of operation.
2. Skill goal: master the sequence of addition and subtraction operations and perform oral calculations correctly.
3. Emotion, attitude and values: in the game middle school, let students like learning and enjoy learning; Looking for mathematical problems in life, initially experiencing the fun of using knowledge to solve problems, and increasing the motivation and confidence of learning.
4, mathematics literacy training objectives:
1) application consciousness;
2) Pay attention to everything in daily life, learn to look at problems from a mathematical point of view and solve problems with mathematical thinking.
Fourth, talk about the difficulties in teaching.
1, key points:
1) express your meaning in your own words and understand the meaning of addition and subtraction;
2) Master the operation sequence.
2. Difficulties: the operation sequence of addition and subtraction.
Fifth, talk about the teaching process.
1, create a scene to stimulate learning.
At the beginning of class, I use the demonstration of courseware to let students fully perceive and express their ideas through their own perception, so as to cultivate students' understanding and speaking ability. Moreover, according to the actual situation of students, we can use the transfer of old knowledge to make students feel the difference between today's addition formula and the previous addition formula, thus leading to continuous addition. After the introduction of the topic, it is not a rigid description of the operation order, but for students to write their own formulas and calculate themselves. At this time, students' interest is very high. Teachers take this as an opportunity to let students talk about how your deskmate calculates, and adopt the teaching method of independent exploration and bold attempt to let students construct the calculation order, which naturally produces the budget order.
After students initially understand the meaning of continuous addition, they use dynamic exercises to make their thinking transition from image to abstraction. When students report, cooperate with the courseware to highlight the calculation process, further consolidate new knowledge and lay the foundation for continuous reduction of learning.
2. Continue the plot and learn less.
It is the nature of every child to show love, so that children have the opportunity to show it and increase the time for intentional attention. Therefore, in teaching design, let students use their imagination, first write the formula of continuous reduction, and then compile the topic through their own formula to fully understand the significance of continuous reduction. Show me the blackboard, because the dynamic diagram of continuous reduction formula is easier to understand, so I ask students to look at the static diagram to describe what happened and understand the meaning of continuous reduction as a whole.
3. Observe and compare, and summarize the algorithm.
Through the above study, students can basically master the meaning and operation order of continuous addition and subtraction. But these are still two independent knowledge points in students' knowledge base, and some students may have a vague understanding of the relationship between addition and subtraction. At this time, I guide students to build a bridge to add and subtract knowledge points, form connections and build their own knowledge kingdom.
4. entertaining and entertaining.
First-year students' attention is easily distracted, and it takes great skill to keep students' attention firmly in class for 40 minutes. Whether in the new knowledge design or practice, it should conform to the psychological and cognitive characteristics of first-grade children. So in the practice part, a suspense is designed, "As long as you guess the mathematical secret under the big footprint, you can lead to a beautiful mathematical castle." The students' appetites suddenly increased. In this process, the game is mainly used to consolidate the new knowledge that students have just learned and highlight the operation order.
Sixth, reflection.
1, I can still let the students observe and express when comparing the operation order of addition and subtraction. Although students sometimes fail to express themselves in place, they are fully affirmed, because this is the bud of children's thinking, and the teacher's affirmation will make them feel that they are great inventors and enhance their confidence in learning mathematics.
2. Although I demonstrated a student's notebook in the practice of watching the calculation circle, it would be better if I took more students' notebooks here to demonstrate and let the students make their own evaluations.
3. After the new lesson, students can cite examples of increase or decrease in their lives.
The second draft of the theory of "increasing with decreasing" says teaching material analysis.
Teaching content: the first lesson of unit 6 "addition and subtraction" in the first volume of compulsory education curriculum standard experiment textbook.
Analysis of teaching materials
In the new curriculum standard, the specific goal of developing students' computational understanding in each learning stage is clearly pointed out. This unit is the method and steps of connecting with students' life practice, allowing students to experience continuous addition and subtraction, thus initially cultivating students' observation and exploration ability. This is an important basis for cultivating students' learning to carry and abdicate subtraction within 20, and it is also one of the difficulties of this unit. Mainly in the calculation process, it takes two steps to work out the result, especially in the second step, which uses the number calculated in the first step, and students often forget the number calculated in the first step. In order to help students master the calculation order of addition and subtraction smoothly and overcome the calculation obstacles, we focus on training students to remember the calculated numbers in their minds, and the effect is very good.
Teaching objectives, key points and difficulties
The overall goal of mathematics curriculum in the Standard is embodied in four aspects: knowledge and skills, mathematical thinking, problem solving, emotion and attitude. According to the above four points, combined with the actual situation of this class, I have formulated the following teaching objectives.
(1) Let students understand the meaning of addition and subtraction, master the operation order of addition and subtraction, calculate correctly, and cultivate students' oral expression ability. (Knowledge and Skills Objectives)
(2) Let the students arrange the pictures in order, find out the rules, cultivate the initial exploration consciousness and experience the fun of learning. (Ability training goal)
(3) Initially cultivate students' habit of calculating in a certain order. (Quality training objectives)
(4) in the activities to guide students to compare, reason and other thinking activities, so that students feel.
Mathematics is around, and it is interesting to study mathematics in order to get a good emotional experience. (Emotions, Attitudes and Goals)
Teaching emphasis: understand and say the meaning of continuous increase and continuous decrease.
Teaching difficulties: according to the meaning of pictures, find out the rules and cultivate students' exploration ability.
Design of Oral English Teaching Methods and Learning Methods
This lesson should enable students to gain relevant experience in the specific life process, not only as knowledge points, but also on the basis of existing experience, so that students can gain experience and understanding. Combined with the characteristics of the first-year students in this class, such as liveliness, thirst for knowledge and rich learning materials, I designed the following teaching methods and learning methods, which not only pay attention to choosing flexible teaching methods, but also pay attention to guiding students to learn methods.
1, creating scenes, connecting with real life, figurative method.
Create a scene of feeding chickens, guide students to observe the theme painting, and let students intuitively understand the calculation steps and methods of continuous addition and subtraction.
2. Observe and discuss, and explore research methods.
The new curriculum standard especially advocates independent, exploratory, cooperative and practical learning methods, and requires guiding students to take the initiative to participate, practice in person, think independently and explore cooperatively. In the classroom, students are guided to observe and discuss, feel life, and carry out teaching closely with their own life experience. Through personal life and labor, students are guided to further understand the calculation steps and methods of continuous increase and decrease, cultivate their ability to apply knowledge and enhance their observation consciousness.
3, hands-on operation, active activity method.
Through teachers giving passwords and students counting their fingers, students can deepen their understanding of the calculation steps and methods of "addition and subtraction", initially perceive the connection between calculation and life, and cultivate their application consciousness.
Teaching preparation
Multimedia courseware fruit
Class arrangement
1 class hour
On the Teaching Process
First of all, ask questions with passion and introduce new lessons.
Teacher: Children, there is a child just like you. His name is Xiaoming. His family has a farm. He is a child who loves to work and often works at home. Today, he came to help his parents. Look! What is he doing? (Showing multimedia courseware, Xiaoming is feeding five chickens) Excuse me: How many chickens are eating rice on the ground now?
Second, observe and explore, learn and supplement.
Show the scene of feeding chickens, the teacher operates step by step and the students observe;
Operation 1: Five chickens are eating rice, and two more come.
Teacher: What do you know when you see this? How many chickens are there? How did you work it out? ) Who can list?
Blackboard writing: 5+2
Operation 2: 1 Here we go again.
Teacher: What do you want to say to everyone at this moment?
Health: Here we go again 1.
Teacher: Who can write formulas? Health said. Teacher's performance: 5+2+ 1=8 Who can read this formula? Reading: Five plus two plus one equals eight.
How to calculate?
Summary: The formula of adding three numbers together like this is called continuous addition. When calculating, you must first remember the sum of the first two numbers in your mind, and then add the third number to the sum in your mind to calculate the result. What does this addition formula mean? Can you count and talk with your fingers like a chicken? )
Third, reduce learning constantly.
Teacher: Match the above scenes and let the students guess what will happen to the chicken after eating the food.
Health: I went to play again and walked away.
Show the courseware, let the students look at the pictures and tell the meaning. Please stand up and point to the picture and say it. )
Health: There are eight chickens. After dinner, there are two left, and then there are two left. How much is left?
Listing: 8-2-2 = 4
Teacher: What does 8224 mean here? Can you read this?
Health: Read: 8 minus 2 minus 2 equals 4.
Summary: The formula that three numbers are connected with a negative sign like this is called continuous subtraction. When calculating, remember the first two numbers, and then cut off the third number from the first two numbers to calculate the result.
Fourth, consolidate and deepen.
Do: Look at the two questions in the textbook and say the meaning with your hands.
Key point: let students further understand whether subtraction is represented by crossing out or circling out.
Feedback: What is your formula? what do you think? How to calculate? Students evaluate each other. Finish the exercise.
Verb (abbreviation of verb) extracurricular expansion
Students talk about increasing and decreasing examples in life.
Six, blackboard design:
Continuous increase or decrease
5+2+ 1=88—2—2=4
Say summary reflection:
Integrate theory with practice, innovate scientifically, be interested in learning mathematics, actively participate in discussions and exchanges, actively and boldly express their opinions, and be willing to listen to the opinions of other children.
Through the teaching of the above links, I think students' thematic role can be brought into play, students are willing to learn, take the initiative to participate in mathematics activities, and their computing ability can be initially cultivated, which can achieve the expected goals.