Teaching Design of "Preliminary Understanding of Fractions" in Junior Middle School Mathematics
Teaching content:
Compulsory education curriculum standard experimental teaching materials, the first volume of the third grade mathematics unit 7 "Preliminary understanding of fractions" will be known in the first class.
Teaching objectives:
1, let students know a little and read a little.
2. Cultivate cooperative learning consciousness, mathematical thinking and language expression ability through group cooperative learning activities.
3. In the hands-on operation, observation and comparison, cultivate students' exploration spirit and autonomous learning ability, so that they can obtain successful experience in solving problems by using knowledge.
Key points and difficulties:
Know a little, read a little.
Preparation of teaching AIDS: courseware, rectangular pieces of paper, umbrella, scissors, glasses, balls, red and blue pencils, five-pointed star, rubber sheet, puzzle, paper flower, Mi Zige exercise book, windmill.
First, import:
Teacher: What do you think of the weather today? What do people like to do in the suburbs on such a sunny day? Look! Today, students of Xin Lei Primary School are having a picnic in the suburbs. Before the activity, Xiao Ming and Xiao Li want to share the food they brought. How to share these things? Who will help them?
1, let's see how these four apples are divided first.
Can you tell me about the calculation method and process? Why do we have to have two each?
Next, let's see how to divide the two sausages.
Can you say method like XXX?
3. Are their methods good? Why? (Do you really think)
Second, the introduction of new courses.
Our classmates in Class Three (Five) are not only clever, but also considerate. Everyone gets the same thing. In mathematics, we call it division? Average score.
1, these are not the most difficult, the most difficult to solve is still there? How do you divide this biscuit? How to divide it is fair.
Divide this biscuit into two parts on average, each part is half of it, so how can this half be expressed by numbers? Can it be expressed by the integer "1"? what do you think?
Yes, we can't use integers to represent this half any more. We should express it in fractions. See how the teacher writes 1/2. Write down the average number of copies of this biscuit "-",and then take a few pieces and write them on it. First of all, praise your courage and dare to make bold guesses.
4. Read from the teacher: half.
There are many members in the 5.score family. Learn a few points in this class first. Please open the textbook on page 92.
6. blackboard writing: a score
7. If the wafer in our hand is this biscuit, you can fold it and divide it into two parts equally.
8. Are they all folded? The teacher wants to ask a classmate, which score can you use to represent this half, and what about this half? How many 1/2 are there in this disc? Then why can this half be represented by 1/2?
9, this sentence is the most important, I want to write it down.
10, read it together.
Three. Origami manual
1, we will find the circle. Can you find rectangles, squares, triangles and diamonds? Fold it first and then show it in the shadow? Ok, let's begin. Let's see which student moves quickly and beautifully.
2. How on earth did you express this paper? Who wants to show their works on stage?
You did it quickly and well, thank you.
4. Are there any classmates who are different from him?
5. Oh, there are different folding methods here. You see, XXX was folded vertically just now, and this student folded the paper horizontally. Do you think that the colored part is also this rectangular paper, so the blank place is it?
6. Since it can be folded horizontally and vertically, how can it be folded? Yes, it can also be folded obliquely.
7. We see that the colored parts of these figures have different effects? But they can all be used to express? Why is this?
practise
1. Next, let's see if the colored part is represented by the following score, right?
2. Can the second figure be used to represent the colored part? Do you have any different opinions? Oh, no, but I have a question. It is divided into two parts. Why can't you express it? Who will help me answer this question?
3. Why can't this triangle be used to represent colored parts? If we divide this into two parts, where should we start?
Iv. Learning 1/4, 1/5
1. I heard that the students in Class 3 (5) are very clever. The Monkey King was not persuaded. He came up with a question to test everyone. Dare you accept the challenge? He said: There is a big cake in front of me, Master, Pig and Friar Sand. If we want everyone to get as many cakes as possible, how should we divide them? How many cakes can everyone get? (Student answers)
2. blackboard writing: 1/4
3. How many1/4 are there?
Who can help this beautiful girl solve the following problem?
Just now we divided 1 biscuit as a whole. Now, what should we take as a whole? How should I divide it? (Talking to each other at the same table) Who has decided?
6. blackboard writing: 1/5 how many 1/5 are there here?
7. Whether we divide cookies, cakes or apples, as long as we divide them equally, each one is a fraction of it. (All students read together)
8. It seems that everyone knows a lot about grades. Let's see if you can report the score shown in the picture as soon as possible.
9. Things in life often have some scores. See what marks are hidden in this umbrella in the teacher's hand?
(1) We divide the umbrella cover into eight parts, each part is 1/8.
(2) What score is hidden in this umbrella?
10, do you want to find your own score in life? According to the articles prepared by the teacher, observe and discuss in groups of four, and tell which part of the articles you found.
1 1.
Verb (abbreviation of verb) summary:
Students, after this class, do you feel that mathematics is everywhere? As long as you are a concerned child, you will find how wonderful and interesting the mathematics kingdom is! Open your eyes and activate your brain, and your world will become more and more exciting.
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