First, the textbook 1, a brief analysis of the textbook

The calculation of parallelogram area is taught on the basis that students have mastered the calculation of rectangular area, the concept and unit of area and the understanding of parallelogram. Based on the method of counting squares, the textbook uses the idea of transformation to transform a parallelogram into a rectangle by digging and filling, and analyzes the relationship between the area of the rectangle and the area of the parallelogram, and then deduces the area calculation formula of the parallelogram from the area calculation formula of the rectangle. Then through the verification of an example, let students understand the derivation process of parallelogram area calculation formula and master the formula on the basis of understanding. At the same time, it is also helpful for students to understand the derivation method and prepare for the derivation of triangular and trapezoidal area formulas.

2. Teaching objectives:

(1) Guide students to deduce the area formula of parallelogram by themselves, and communicate the internal relationship between rectangle and parallelogram.

(2) Through operation, let students try to solve new problems with transformed thinking methods.

(3) Understand that the area of parallelogram is related to the base and height, and use the area formula to find the area of parallelogram.

3. Teaching emphasis: area calculation of parallelogram.

4. Teaching difficulty: understanding the derivation process of parallelogram area calculation formula.

Second, the teaching law

The calculation of parallelogram area is a preparatory knowledge course of geometry, which provides knowledge preparation for studying the calculation of triangle area and trapezoid area in the future. The teaching design of this course is from intuitive to abstract, and goes deep at different levels. The initial feedback is summarized from hands-on observation, thinking and induction, following the principles of concept teaching and students' cognitive laws. Through hands-on operation, the parallelogram is transformed into a rectangle, and the existing representation is reproduced. With the help of existing knowledge and experience, the calculation formula of parallelogram area is observed, analyzed, compared, reasoned and summarized. This just reflects the order of concept teaching: action perception forms abstract concepts.

Students' dominant position is fully reflected in teaching, and students' enthusiasm and initiative are fully mobilized. Guide students to operate, observe, compare and explore independently, attach importance to allowing students to operate and acquire knowledge independently, and take thinking training as the main line to improve students' thinking level. Cooperate with each other, take all students as the educational object, improve as a whole, and create a good learning atmosphere.

Third, the teaching process

(1) review and preparation

Show teaching AIDS one by one:

1, what is the graph (1)? How to calculate its area? Now it is 7 cm long and 4 cm wide. Do you know the area of this rectangle?

2. The area of a rectangle can be directly calculated by a formula, so can we directly calculate its area by the formula in Figure (2)? How to find its area?

Students think independently and give feedback after discussion. Teaching aid demonstration: cut out an extra piece and put it into a rectangle. Multiply the length by the width to get its area. )

3. Just now, we converted the figure (2) into a rectangle with the same area as the original figure by cutting and mending, and then calculated its area with the rectangular area formula. Who can calculate the area of Figure (3) now?

Students give feedback after independent calculation. How to calculate it? Why? (Teaching aid demonstration: Cut the triangle on the right in Figure (3) and fill it to the left to become a rectangle. )

(B) the introduction of new courses

Figure (2) and Figure (3) We can calculate their areas by cutting and filling them into learned rectangles. (The teaching aid is shown below)

Can you work out the area of this parallelogram? Let's study the area calculation of parallelogram together. Show me the topic.

(3) Guiding the investigation

1. Students think independently and operate by hands, trying to calculate the area of parallelogram.

(Teachers patrol, students calculate the parallelogram area of study tool paper No.65438 +0)

Who can tell what the area of this parallelogram is? How to calculate it? Students may have different answers.

What is the correct way of thinking? Make full use of your school tools and related tools (ruler, scissors, etc. ) to try out the operation, and then calculate it in tabular form (four-person group cooperation and exchange)

Feedback communication: According to the students' answers, demonstrate the "transformation process".

Before the demonstration, compare two congruent parallelograms, then cut one of them along the height of the parallelogram, and put the triangle on the left (or the trapezoid on the right) to the right, which is exactly a rectangle. Measuring its length is 7 cm, its width is 4 cm, and its area is 7×4=28 square cm.

Follow-up: Why can this be calculated?

Cut the parallelogram into a rectangle. What has changed and what hasn't?

Compare the length and width of the spliced rectangle with the base and height of the original parallelogram.

2. Practice and verify ideas.

Can all parallelograms be converted into rectangles? Draw a parallelogram at will or take a piece of paper with learning tools at will to prove your idea. (Conclusion: From this point of view, to calculate the area of any parallelogram, we can use cut-and-fill access to convert the parallelogram into a rectangle to calculate its area. )

3, observation and analysis, induction formula.

So how to calculate the area of parallelogram? Why? (Students discuss)

Combined with the answer, teaching aid demonstration: because the parallelogram is transformed into a rectangle by cutting and filling method, the deformation area remains unchanged. We find that the length of a rectangle is equivalent to the base of a parallelogram and the width is equivalent to the height of a parallelogram, so the area of a parallelogram is the base multiplied by the height.

Blackboard writing: rectangular area = length × width

Area of parallelogram = base × height

If the letter S represents the area of parallelogram, A represents its base and H represents its height, what is the letter formula of equilateral quadrilateral?

(4) Summary

1. Facing the new problem of "area of parallelogram", the area formula of parallelogram is derived by using the existing knowledge of "finding the area of rectangle".

2. Now, tell me, what are the two key conditions for finding the area of parallelogram?

(5) Practice

1. Calculate the area of the parallelogram below. (Comments after practice)

2. Calculate the area of the parallelogram below.

3. There is a parallelogram grassland with a base of 18m and a height of 10m. What is the area of this meadow?

(6) Class summary

1. What have we learned in this lesson? What experience do you have?

2. How are the students doing?

*3 maneuvers:

Calculate the area of the parallelogram in the figure below, and the correct formula is (). (Unit: cm)

extreme

Let's talk about the textbook 1 and the content of the class:

Compulsory Education Curriculum Standard Experimental Textbook (People's Education Edition) Primary School Mathematics Textbook Volume 5 Unit 7 "Preliminary Understanding of Fractions" What to do with "Understanding of Fractions" and Page 93 in the initial teaching.

2. The position, function and significance of teaching content:

This part is a preliminary understanding of the meaning of fractions on the basis that students have mastered some integer knowledge. From integer to fraction is an extension of the concept of number. Fractions and integers are quite different in meaning, reading and writing methods and calculation methods. Students will find it difficult to get grades for the first time. Scores are unfamiliar to students, but "half of objects and figures" is familiar to students. Therefore, this lesson mainly starts from the practical experience that students are familiar with and interested in, and helps students understand the specific meaning of some simple fractions through hands-on operation, so that students can realize that fractions come from life and can only be generated under the condition of "average scores", and establish a preliminary concept of fractions for students, laying a preliminary foundation for further learning fractions and decimals.

3. Teaching objectives:

(1), know the score in specific situations and establish the initial concept of the score.

(2) The fraction of the molecule "1" can be compared intuitively.

(3) Communicate the connection between life and mathematics, and perceive mathematics in life.

4, the arrangement characteristics of teaching content:

(1), the textbook presents the basic learning content of this unit in the form of "amusement park", which embodies the understanding of mathematics in the game and the organic connection between man and life and nature.

(2) "Know a score" introduces a score through the scene that two students divide a moon cake, so that students can know that a moon cake is divided into two parts on average, and each part is half of the moon cake, that is, half, and write it out. Inferred by migration, it is divided into several parts on average, and each part is a score of it.

(3) Students can score by hand. First, create a learning situation, pay attention to the operability of imparting knowledge, let students fully perceive the score, and compare the score with the molecule "1".

5. Teaching emphases, difficulties and keys

Understanding that only the average score can produce a score, and understanding a score is the focus of teaching; It is difficult to compare the meaning of the perception score with the score with the numerator "1". The key to teaching is to provide students with as many materials as possible. Through folding, playing, drawing and other activities, let students fully perceive the meaning of the score, and compare the score with the molecule of "1", and attach importance to the development of students' thinking.

Second, oral teaching methods

The main idea of designing this lesson is to strengthen intuitive teaching, reduce cognitive difficulty, and let students explore the meaning of fractions in folding, drawing and playing, and experience the formation process of mathematical knowledge by themselves. In line with the "New Curriculum Standard": "Effective mathematics learning activities can't rely solely on imitation and memory. Hands-on practice, independent exploration and cooperative communication are important ways for students to learn mathematics."

Third, theoretical study.

1. Understand the "average score" through intuitive graphics and objects, and then perceive the meaning of the score.

2. Compare, learn mathematics in hands-on practice, and learn to observe life from a mathematical perspective.

Fourth, the teaching design of this class is mainly divided into four links:

1, activity introduction, experience average score.

2. Actively explore and feel new knowledge. (From surface to point)

(1) Understand a fraction: average score-the meaning of denominator-the meaning of a fraction-reveal the topic.

(2) Understanding 1/2: Different graphs are represented by the same score.

3. Use student resources (hands-on operation) to compare scores.

4. Find scores in life and let students experience the source and life of scores.

Teaching program design

Introduction: (The new curriculum standard points out that we should pay attention to learning and understanding mathematics from students' practical experience and existing knowledge. So when I design this class, I start with the apple that students are most familiar with, so that students can feel the average score)

1, create a situation, Congcong and Mingming divide six apples, how to divide them?

Health 1: ...

2. Teacher: Which of these two methods is the most special? Why? (special "average score") blackboard writing

3. If two apples are given to two people, how to divide them?

Student: One for each person.

Show me an apple for two people. Can we split it equally? How to divide it?

5, students take the circle as an example to operate, and the same size is folded in half, which is the average score. (The initial understanding of the meaning of the score is based on the average score)

Second, the score teaching (many perceptions divide a thing into several parts on average, and then reveal the score on the basis of taking one of them. The purpose is to reduce the degree of teaching and let students explore independently.

1, please select the figure you like in the envelope, fold it in half and divide it into one point. What's your difference? Colour one of them. (Students operate with hands, and teachers patrol to understand the situation)

2. Feedback: (Put the students' works on the blackboard and number them. There are three 1/2, 1/3, 1/4, 1/8, 1/6,1/6 and1.

Teacher: Are these figures equal? Why? Today, let's study the average score first.

Teacher: Why do you think these are average scores? (each share gets the same amount, that is, the average score)

3. What's the difference between these average scores? (1) (the average number of copies is different)

(2) Divide () into () ...

4. (Ask questions flexibly according to question 3, all or some) Let the students talk about the meaning of the pictures. (For example, divide a square into n parts and blot out one part)

5. Teacher: (takes out a graph) The whole graph is represented by 1, so the graph is divided into two parts on average. What is the number of this part? (If a student can't speak for himself) Know 1/2, 1/3, 1/4 ... (Insert writing method here) Write on the blackboard with various fractions under the graphics, and teach reading methods.

6. Teacher: Why do you use 1/2 for this and 1/4 for that?

Student: The average number of shares is different. Divided into two parts on average, divided into four parts on average.

7. Expose topics: like these 1/2, 1/3, 1/8 ... we all call them scores (blackboard writing: scores).

8. For example, 1/4 is to divide a square into four parts, one of which is square 1/4.

How many 1/4 are there in the blank part?

8. Exercise: (True or False)

Third, teaching 1/2 (further understanding the meaning of the score)

1, (The teacher uses 1/2 to draw down the students' works) Let's look at these works, which are all expressed by the score of 1/2. Why can different graphs be represented by the same score 1/2?

Summary: (The similarity of these graphs can be expressed by 1/2) Divide () into two parts on average, and each part is its 1/2.

2. Teacher: Which number is used to represent the blank part? Why?

3. (Again) What does 1/2 mean? What does 2 mean? What does 1 mean?

Choose a score and say what it means.

Fourth, compare the scores.

1, (Take out two identical numbers 1/2 and 1/32) Let's look at these two numbers. The colored part is represented by 1/2 and the colored part is represented by 1/32. Which is bigger? Why?

(1/2 means that a graph is divided into two parts on average, one of which is larger than a graph divided into 32 parts on average).

Blackboard:1/2 > 1/32

2. Guess the size of 1/2, 1/8, 1/32.

Blackboard:1/2 > 1/8 > 1/32

3. Free to choose two scores for comparison. What did you find? (The more copies, the smaller)

4. Say a smaller score.

5. The scores in life (the scores are around us). How many points do you associate with these?

A, what score do you think?

B, expanding exercises

Tisso

Teaching process: 1. Stimulate interest in the scene and introduce new courses.

1, Teacher: In recent classes, we have learned a new number-fraction. Can you say the score?

Let the students give an example and say how he got this score.

2. Teacher: Teacher Chen just saw a car sign on the way to your school (the teacher showed a BMW sign).

Can you find the score in this symbol? (Health 1: The blue part is 2/4 of this sign. Health 2: The blank part is also 2/4 of this sign. )

3. Teacher: Teacher Chen got another point while eating chocolate. Can you guess how many points the teacher got? (showing chocolate)

(Health 1: Teacher Chen ate one of them, which is 1/6 of this chocolate. Health 2: Eating three servings is 3/6 of this chocolate, and eating four servings is 4/6 of it. Health 3: Eating it all is 6/6 of this chocolate. )

Second, explore the addition of fractions with the same denominator.

1. What do you think when you see 2/6 and 3/6 on the blackboard? (2/6 is less than 3/6 with the same denominator ...)

2. Teacher: Can you ask a math problem according to the chocolate that several students ate just now?

There are several different versions now. How can you convince others to accept your version? (Ways to prove yourself)

Now, please use your favorite method to prove that your statement is correct, so that everyone can accept your statement, ok? (For example, you can draw, fold, write, and even organize languages.)

Student operation, teacher patrol guidance.

5. Show the report and talk about ideas.

Health 1: Our group thinks it should be 5/6. For example, chocolate should be eaten twice, which is 2/6 of it, and then eaten three times, which is 3/6, so it is 5/6.

Health 2: I am origami.

(Showing folded paper:) 2/6 is 2 sheets, 3/6 is 3 sheets, and1* * is 5 sheets, so 2/6+3/6=5/6.

Teacher: How much is 2 yuan 1/6?

Health: two, three is three 1/6.

Teacher: How much is it altogether?

Health: five 1/6 is five/6.

Teacher: Does anyone draw?

Health: I drew a rectangular picture. (Physical projection display)

6. Can you count the others? For example, 1/6+3/6(5/6)

Tell me your opinion (1 1/6 plus 3 1/6 is 4 1/6, which is 4/6).

Guide students to sum up math: two 1/6 and three 1/6 are five 1/6, which is 5/6.

7. Well said! You can add up two scores on the blackboard, or you can write two scores and add one.

Oral report, grab those that add up to more than 6/6, such as 1/6+6/6=7/6, and ask students to explain why they are not 1/7, and be reasonable.

Thirdly, the research of fractional subtraction with the same denominator.

1, then who will calculate 4/6-3/6 and who will explain the method.

Similarly, four 1/6- two 1/6 is two 1/6 is two 6.

Can you choose some scores from the blackboard, write some formulas and work out the results?

Step 3 report and show it

How to calculate it? (The denominator is the same, just subtract the numerator. )

4. A piece of chocolate, the teacher ate 1/4, how much is left?

Teacher: What number should I use for chocolate bars? (represented by 1

How to solve this problem? How to form?

Teacher: Try to calculate.

Health:1-1/4 = 4/4-1/4 = 3/4.

Take 1 when 4/4, four 1/4 minus 1/4 equals three 1/4, which is 3/4.

Summary: When we subtract a fraction from 1, we regard 1 as a fraction with the same numerator and denominator.

Fourth, solve the problem.

1, calculating

1/4+2/42/8+5/86/8+3/83/5- 1/5=7/9-5/9= 1-7/9=2/3-2/3=

Verb (abbreviation of verb) summary after class

What did we learn in this class? What did you get? What problems should we pay attention to? Is there a problem? The student said no problem. You have no problem. Let me ask you a question: 1/2+ 1/4, 1/2- 1/4. Can it be solved?

6. Blackboard design:

Simple calculation of fraction

1/62/63/64/65/66/6

2/6+3/6=4/6-2/6=

1- 1/4