Grade: Grade 5

Lecturer: Dear Zhang.

Subject: Equation

teaching process

First, import

Teacher: What do we call it when we go to the market to buy things?

Student: Scale, electronic scale.

Teacher: Have you ever seen such a scale? Show me the balance.

Second, introduce the balance.

It has two trays, with a scale in the middle, two-day scales are equal, and the middle scale is 0. This is balance.

Third, explore new knowledge and watch courseware.

(1) equation

1, put weights on both sides of the balance, the left plate: 20g and 30g, the right plate: 50g, and the middle scale points to 0, indicating the balance of the balance.

Question: Can you list a formula on this basis?

Student: 20+30=50

2. Look at the courseware and the formula.

30+x=80 x+20=70 2x= 100

3. What is an equation? The students said together: the formula of equality is called equality.

For example: 60+x=80 70+20=90 50-20=30.

4. Summary: What we just said is an equation. Let's find an equal relationship first An equation is a formula for expressing equality.

5. Counterexample: Is 5x & gt29 30 & lt70 an equation?

Student: No.

6. Say the concept of equation twice.

(2) Equation

1, what are some expressions like 30+x=80, x+20=70, 2x= 100?

Student: Equation

Teacher: It seems that this classmate previewed this section, which is worthy of praise.

2. Yes, this is an equation. An equation containing unknowns like this is called an equation. Read repeatedly. Give an example of an equation.

3. The relationship between equation and equation.

All equations are equations, and all equations are not necessarily equations.

(3) Write on the blackboard

20+30=50

An equation representing equality is called an equation.

30+x=50

x+20=70

2x= 100

Equation with unknown number

Fourth, practice

1, judge which are equations and which are equations? Why?

2. Look at the picture equation and say what it means.

Verb (abbreviation of verb) abstract

What is an equation? Equation?

The expression of equality is called equality.

Equations with unknowns are called equations.

Comments on the lecture:

1. Introduce things from life to attract students' attention.

2. The classroom arrangement is logical: equivalence-→ equation-→ equation.

3. On the blackboard, we pay attention to distinguish with colored pens and describe the concepts clearly.

I take care of most students in class and can treat them equally.

5. When emphasizing the key points, adopt the method of reading more and reading more to deepen students' impression.

Notes of Primary School Mathematics Teachers (Part II) (1)

Teacher: As soon as I entered our Class 4 (9), I felt very warm. Why do you say that? Because some students greet me with warm words; Some students greeted me with sweet smiles; Some students face me with a correct sitting posture, which makes me eager to join your math trip today. First, let the teacher see your math ability. Show courseware: What can I fill in the brackets? )

Health: The maximum number of brackets can be 7.

Teacher: Why should I fill in 7?

Health: Because 3 16 has at most seven 40s.

Teacher: That's good. The teacher wants several students to finish the following questions in this way.

Teacher: It seems that these questions are not difficult for students. Please look at a few more questions, and you can hurry up.

What is the quotient? (Show the courseware: Think about it, what is the quotient)

Health: the quotient is 8.

Teacher: Why do you think of quotient 8?

Health: Because 165 has eight twenties.

Teacher: The quotient of 165 divided by 20 is 8, so what is the quotient of 175 divided by 20?

Health: 8 and 9.

Teacher: The divisors are all 20. Why is the quotient of 165 divided by 20 175 divided by 20 8 and 185 divided by 20 9?

Health: Because 165 175 has at most eight twenties, but 185 has at most nine twenties.

(2) There is no end to learning.

1. Learn Example 3( 1)

Teacher: Great. It seems that the students in Class 4 (9) have a solid foundation in mathematics. In order to reward everyone, the teacher took everyone to the mall. This is the stationery counter (showing courseware). What mathematical information did you find?

Student: A pencil-box 2 1 yuan, a desk lamp 62 yuan, a calculator 29 yuan and a football 38 yuan.

Teacher: That's true. Xiaohong is also shopping. She came to this stationery counter and asked such a math question (show the courseware). Who will read it?

Health: I have 84 yuan. How many pencil boxes can I buy?

Teacher: Can you help her solve it?

Health: Yes.

Student: 84 ÷ 2 1 = 4 (a) (teacher's blackboard)

Teacher: You are really something. You worked out the result directly with your mouth. The divisor and dividend of this problem are relatively small, and you can see what quotient is at a glance. Divider and dividend are relatively large. What should I do if I can't do it directly with my mouth?

Health 1: estimate.

Health 2: You can use a pen to calculate.

Teacher: (writing on the blackboard) Before, we learned how to calculate the divisor by writing. Here, the divisor 2 1 is not an integer ten. How to treat business? 2 1 How much is a quotient?

Health: Take 2 1 as 20.

Teacher: Why is it 20?

Health: Because 2 1 is closest to the integer 20.

Teacher: How much can I negotiate?

Health: quotient 4.

Teacher: Why do you think of quotient 4?

Health: Because there were four twenties in' 84.

Teacher: (Write on the blackboard 4)4 Write it in one place. Next, let's see if this 4 is ok. Should I divide by 4 times 20 or 2 1?

Health 1: times 20.

Health 2: Take 2 1.

Teacher: What is the divisor of this question (2 1), so multiply 2 1 by 4 to equal 84 (vertical blackboard writing), and then test how this 84 comes from? (Students answer 4×2 1) The product is equal to the dividend. Can't this firm work?

Health: OK.

Teacher: The product can be equal to or less than the dividend, but not more than the dividend. (perfect blackboard writing)

2 Learning Example 3(2)

Teacher: Xiaoming came to the stationery store, and so did Xiaohong. Let's see what math problem Xiaohong asked. (Showing the courseware) Who will watch it?

Student: I have 430 yuan's money. How many lamps can I buy?

Teacher: Can it be solved?

Health: Yes.

Teacher: Please take these questions and try to do it by writing (showing the courseware).

Students visit teachers independently, find two different methods, and ask students to write on the blackboard.

Teacher: Good students can exchange questions with each other on the blackboard.

Teacher: Please look at the blackboard. This is done by two students. Let's look at this classmate's first. He wrote two vertical forms. Let's hear his thoughts.

Health 1: I'll take 62 as 60 first, because there are seven 60s in 430, so the product of quotient 7 multiplied by 62 multiplied by 7 is 434. I found that the product is greater than the dividend, which means the quotient is greater. Adjust the quotient to 6, the product of 6 times 62 is 372, and the remainder is 58.

Teacher: That's good. Let's listen to the idea of this classmate who only wrote the vertical body.

Health 2: I first estimate 62 as 60, and think of quotient 7. When I multiply 62 by 7, I find that the quotient is big, so I change it directly to quotient 6.

Teacher: That's what they all think. Everyone thinks of 7 first, and when they find that the quotient is 7, it drops to 6. Students, think about why the quotient is too big.

Health: Because we underestimate the divisor, the quotient is often too large.

Teacher: Let the students and the teacher finish the blackboard together. When the students say this, I will write out the process of thinking. (The teacher summed up the words "evaluation, examination, multiplication and adjustment")

(3) 100% tempering into steel

1 calculate.

Teacher: You are really something. You helped Xiaoming and Xiaohong solve the problem so quickly. Teacher, are you confident to solve these two problems?

Health: Yes.

Teacher: (Show the courseware and look at the questions) Ask one or two groups to solve the first question, and three or four groups to solve the second question, which is faster than one group.

Students do the teacher patrol independently, put the notebook with two vertical students on the projector, and let the students express their thoughts.

Teacher: We can also do what some students do (put a classmate's notebook with only one vertical writing on the projector).

They put the process of thinking about quotient and trying quotient in their hearts and write the exact quotient directly. You can do it directly when you are skilled in the future.

2 estimate an estimate

Teacher: Do students have a special sense of accomplishment? When they visited the shopping center, they helped many people. Next, we go to the children's playground on the seventh floor of the mall to play (show the courseware). Tickets for children's paradise are not bought with money, but obtained by wisdom. I think some students are very moved, but their hearts are not as good as theirs. Let's have a look! Please ask one group to help the blue house find its owner, the second group to help the green house find its owner, the third group to help the yellow house find its owner and the fourth group to help the red house find its owner.

Report the results after the students are divided into groups.

Three to one

Teacher: After successfully passing the first level, let's take a look at the second level (showing courseware). Who can tell the exact quotient according to the test quotient? )

Answer first.

Teacher: The collective power is really great. We got the tickets by collective wisdom. I declare that all students in Class 4 (9) can enter the Children's Paradise for free. Please close your eyes and imagine playing tag as a child.

4 change it.

Teacher: Have you finished typing? Please open your eyes, you may need your help again. Aunt, the salesgirl at the sporting goods counter, has a problem (show the courseware) (show the courseware and correct it)

(4) Expansion and extension

Teacher: It seems that nothing beats you. Teacher, there is another challenge. Dare you challenge?

Health: Dare.

Teacher: Yes, how can I see the rainbow without experiencing wind and rain? Let's challenge together! (Show courseware) The dividend of this problem is two digits, and it is 6 in ten digits. The numbers on the digits are blocked. Think about what a quotient might be. Please discuss in groups.

Health 1: It may be 4.

Teacher: Is four all right?

Student: No, if it is 4, the product of 4 times 22 is 88, the dividend is 6, and the product is greater than the dividend.

Health 2: It may be 1.

Teacher: Is it 1?

Student: No, if it is 1, the product is 22 and the remainder is greater than the divisor.