Teaching objectives:
1, so that students can initially understand the meaning of problems encountered, understand the meaning of problems with the help of line diagrams, and learn to enumerate comprehensive formulas to solve application problems.
2. Cultivate students' initial logical thinking ability and the ability to solve simple practical problems.
3. Further cultivate students' ability to analyze and answer application questions.
Teaching focus:
Learn to analyze and solve the strategy of accidental application problems, and master the solution to the accidental problem of distance.
Teaching difficulties:
Understanding the quantitative relationship of encounter problems and analyzing the thinking of solving them.
Teaching process:
First, dialogue import
Students, I have a math class with you today to study a common problem in our life-meeting. (blackboard title: encounter problems)
Speaking of "meeting", what do you mean?
Let's think about it. What might the problem have to do with it? (speed, time, distance)
What is the relationship between these three quantities?
Today, the relationship: speed × time = distance is mainly used to study the encounter problem.
Second, the new teaching
(A) Show the problem
Xiaoping and Xiaoming walked across the house at the same time. Four minutes later, they met at school. Xiaoping walks 65 meters per minute, and Xiaoming walks 75 meters per minute. How many meters are they apart?
Who will read it to everyone?
Who can tell the meaning of this passage?
What problem does this passage solve?
Who can explain?
(B) a variety of ways to understand the meaning of the problem
1, give a performance
Can you express the meaning of this passage in other ways than words?
Can we perform the process of two people meeting?
Who wants to perform with the teacher?
How are you going to perform?
Live performance:
(1) Teacher: Any comments?
Why are you going together? (simultaneous reflection)
(2) The teacher goes in the opposite direction (reflecting relative)
(3) Student performance (stopping halfway: reflecting the meeting)
Let's see how Xiaoping and Xiaoming walk. (courseware animation demonstration)
What did you find through observation?
Summary:
How do you feel when we look at this information through our own performance?
Being more and more clear will help us better understand the meaning of the problem.
With the help of performance, we can understand the meaning of the problem more deeply.
Step 2 draw a picture
(1) Can you show the known information and problems in this passage by drawing?
Let's draw a picture in the exercise book and have a try.
(2) demonstration:
Tell me what you think.
Who will comment on what they draw?
Compared with the last classmate, what's good?
Which student do you think draws the known information and questions more clearly?
(Instruct students to draw line segments)
What do you think is helpful for us to solve problems by using line graphs to represent information and problems?
(3) Solving problems
Show line chart: how to solve it?
Students, can you solve this problem now?
Do it in the exercise book.
Report (The teacher writes on the blackboard,
65×4+75×4
Who will explain this practice? (Refer to the line segment diagram and explain it in the front.)
Does anyone have a question?
Teacher: Summary: Distance+Distance = Total Distance.
Who else can make a difference?
Do you have any questions?
Why ×4? Summary: speed and time = total distance
(Ask questions and show methods)
(4) Review and arrangement
Let's recall how we solved the problem of meeting just now.
What have we done? We help us understand the meaning of the problem and clear our minds through acting and drawing, so it is very important to find ways to help when we encounter problems. )
(5) Practice
1. Can you solve the following problems?
Why is this solved?
2. Have the two cars met now?
How to solve it?
Draw a picture in the exercise book.
What did you find?
3. In fact, the problem of meeting is widely used in life:
Will there be any results?
4. Can you understand the following questions? Will there be any results?
Try drawing a picture.
Who will report it? what do you think?
Three. abstract
What did you get from this lesson?
Teaching reflection
"Encountering problems" is taught on the basis of learning simple travel problems. This lesson mainly guides students to explore and analyze the quantitative relationship of problems encountered and learn the methods to solve them.
(1) In the teaching of this course, I pay attention to let students fully participate in the induction of problem-solving methods of "meeting questions". Through full observation, simulated performance and arrangement, students can realize the characteristics and problem-solving methods of "meeting questions", fully mobilize the initiative of students to participate, and initially build their own cognitive system.
(2) The general methods for students to study problems through their own experience are: sorting out information independently-sorting out quantitative relations; With the help of intuitive line drawing-find out the way to solve the problem; Clarify the method of solving problems and solve problems independently-build the mathematical model of application problems independently. Students really become the masters of the classroom, leaving enough space for students to explore and communicate independently. Teachers only supplement or correct when appropriate. In the design of exercises, I pay attention not only to the consolidation of basic knowledge, but also to the needs of students at different levels. Not only can students understand the simple encounter problem in the textbook, but also the simple encounter problem has been revised, so that students can deeply understand the relationship between the three quantities: speed sum, meeting time and total distance, and also extend the engineering problem and expand students' thinking.
Optimal Teaching Design of "Meeting Problem" in Primary Mathematics