Teaching plan design of "5, 4, 3, 2 plus a few" in the first volume of mathematics for the first grade of People's Education Edition

Teaching objectives of the lesson plan "Five, Four, Three, Two Plus Several" (1)

1, let students master the addend of 5, 4, 3, 2, which can be calculated by exchanging addends and thinking about large corner decimals.

2. Cultivate students to learn the calculation of 5, 4, 3 and 2 plus several skills of 9, 8, 7 and 6, so as to improve students' knowledge transfer and calculation ability.

3. Cultivate students' good writing habits and serious and responsible attitude.

Emphasis and difficulty in teaching

The key point of learning is to let students master the addition of 5, 4, 3 and 2, which can be calculated by exchanging addends and thinking about big corner decimals.

Count.

Learning difficulties train students to learn the calculation of 5, 4, 3 and 2 plus several skills of 9, 8, 7 and 6, thus improving students' knowledge transfer and calculation ability.

teaching process

First, review the old knowledge.

1, oral calculation.

9 ten 5= 9 ten 3= 8 ten 5= 7 ten 6= 6 ten 7=

8 ten 4= 6 ten 9= 7 ten 8= 8 ten 7= 8 ten 9=

2. Ask students to calculate orally and tell the thinking process.

Teacher: Students use different methods to calculate. In this lesson, we will continue to use these methods to learn carry addition within 20 of the addition of 5, 4, 3 and 2. (blackboard writing: 5, 4, 3, 2 plus a few)

Second, explore new knowledge.

1, showing 57 =, study together at the same table.

How much is 57? How to calculate?

① Students try to do 57 independently.

② Communicate at the same table and discuss various calculation methods.

③ Students report various algorithms, and the teacher writes them on the blackboard.

Teacher: Students choose the method they like and the method that can calculate accurately.

2. Group exploration 58, 48 and 39.

① Students analyze the algorithm of each problem and write down the numbers in the book.

(2) Report different algorithms and write on the blackboard.

③ Discussion: Apart from examples, what are the problems of carry addition within 20, such as 5 plus several, 4 plus several, 3 plus several, 2 plus several, etc.

The teacher suggested that 1: 20 means that the number range is 1 1 to 20.

Teacher's tip 2: add up with carry, that is, one digit is full of ten, and one digit is entered into ten digits.

The number of students scrambling to answer the report.

3. Reading questions.

4. Do it.

① Look at the picture. (Question 1)

Look at the picture, say the meaning of the picture and calculate it continuously.

② Questions 2 and 3.

Students do their own questions and follow the rules of the upper and lower questions. Through observation, it is found that the addend changes the position and the sum remains unchanged.

5. summary.

In this class, students use many methods to calculate the addends of 5, 4, 3 and 2, including adding to 10 and changing the position of addends. Any method can be used as long as the calculation is accurate.

Third, practice is improved.

1, say the number first, then the formula. (Exercise 22, Question 1)

There is a number on the corner of each graph. Add the number inside and the number outside. According to the change of the outside numbers, say the numbers first and then calculate the formula.

Student report.

2. See who can calculate quickly and accurately. (Exercise 22, Question 3)

One and a half minutes, after the answer, collective correction.

3. Exercise 22, Questions 4 and 5.

Students finish independently and revise collectively.

4. Exercise 22, Question 2.

Let the students understand this table first and let them fill in the numbers in the book. Teachers can encourage students with learning difficulties to ask questions before calculation. )

Fourth, summarize and sort out

In this lesson, we used many methods to calculate the addend of 5, 4, 3 and 2, including adding to 10 and changing the position of the addend. Any method can be used as long as the calculation is accurate.

homework

Complete the questions in the workbook.

Teaching plan "five, four, three, two plus a few" (2) Teaching objectives

1. 1 knowledge and skills: master the calculation method of 5, 4, 3 and 2 plus several, and be able to calculate accurately; Understand arithmetic, master the algorithm in the calculation process, and turn the problem of adding a few to 5, 4, 3 and 2 into the carry calculation of adding a few to 9, 8, 7 and 6.

1.2 process and method: in solving the problem of adding words 5, 4, 3 and 2, let students feel that they can turn new problems into learned problems and establish connections between knowledge; On the basis of students' proficiency in calculation, guide students to observe and discover the phenomenon of additive commutative law from the perspective of calculation.

1.3 Emotion, attitude and values: Initially learn to explore and experience the pleasure of success by means of migration.

Emphasis and difficulty in teaching

2. 1 teaching emphasis: master the general calculation method of adding 5, 4, 3 and 2.

2.2 Teaching difficulties: By exchanging the addend positions, we can understand how to calculate the addend of 5, 4, 3 and 2.

2.3 Test center analysis: Master the calculation method of adding a few to 5, 4, 3 and 2, and be able to calculate accurately.

teaching tool

20 boxes of courseware and learning tools.

teaching process

Review preparation

1 9 plus a few exercises.

2, 8, 7, 6 plus some exercises.

3, 8, 9 and 9, 8 exchange places for practice.

4. Comprehensive oral calculation questions.

Explore new knowledge

1, inspirational dialogue:

We have learned the carry addition of 9, 8, 7 and 6. Today we are going to use what we have learned to learn 5, 4, 3, 2 plus a few (blackboard writing topic).

2. Look at the teacher's questions and compare who is the fastest.

Example 1 5+7=□ 5+8=□

Teacher's blackboard writing: 5+7=□

The teacher asked: Please tell me how you want to get the figures quickly.

Name: (students may say two ways)

(1) Use the method of ten.

(2) Using the method of exchange addend

Think about it: 7 plus 5 equals 12,

Five plus seven equals 12.

2, learning communication method

The teacher said: You can think of both methods. Let's take a look again: what about 5+8?

Blackboard writing: 5+8=□

Students will still say two ways.

(1) Use the method of ten. (2) Using the method of exchange addend.

Think about it: 8 plus 5 equals 13,

Five plus eight equals 13.

Compare these two methods:

The teacher said: Just now, we used two methods to calculate the problem of 5 plus a few. Please compare the results and see which method is faster and simpler.

The student replied: The second method is faster and simpler.

The teacher said: Good! You all like the second method. The second method is to exchange the positions of addends, and think about Osuka decimals. Let the students think about how to calculate 4 plus a few and 3 plus a few.

Example 2 4+8=□ 3+9=□

Blackboard: 4+8=□

The teacher asked: What do you think of this problem?

Name: Xiang: 8 plus 4 equals 12, and 4 plus 8 equals 12.

The teacher said: the students calculate really fast. Let's ask one more question to see who can calculate quickly.

Blackboard: 3+9=□

Name: What do you think?

Ask the students to answer: When you think of the big corner decimal system, 9 plus 3 equals 12, and 3 plus 9 equals 12.

Summary: The four questions we calculated just now are all questions of adding a few points. (It's five, four, three plus a few) How does the front addend compare with the back addend? (The former addend is less than the latter addend. ) This is decimal addition. What should I think when I see such a problem? (thinking of big corner decimal system) Yes! Calculate by the method that the exchange addend position is Osuka decimal. This calculation is correct and fast.

3. Deepen understanding and consolidate.

Example 3 Show Courseware (Bitmap)

Look at the picture carefully:

Q: What does this picture mean? Can you ask a question according to the picture?

Students discuss, ask one student to explain the meaning, and then ask another student to ask questions.

Student 1: There are five green dots and nine red dots.

Student 2: How many red and green dots are there? According to the students' narration, the teacher writes on the blackboard. )

Q: Who can list the formula according to this question?

Student 3: 5+9 =

To discuss the calculation method, please tell your deskmate your algorithm.

A. the position of the exchange addend:

We have learned that 9+5= 14 before, because the sum of commutative addend positions is constant, so 5+9 equals 9+5, 9+5= 14, so 5+9= 14.

B. Ten-point method

Divide 5 into 1 and 4, 1+9 = 10, 10+4= 14.

C. Then count

There are five red ones, so the green ones are 6, 7, 8, 9, 10,1,12, 13, 14.

Finally, 5+9= 14 is obtained.

4. Knowledge application

The teacher asked: In addition to these questions, are there any questions that add 5, 4, 3, 2? Please think about it.

Students write questions, and the teacher writes on the blackboard:

5+6= 4+7= 3+8= 2+9=

The teacher said: You think very well. These four questions are questions of adding a few to 5, 4, 3 and 2, and also questions of adding a few to decimals. Can you work out these figures quickly with the new method you learned today? Who will give it a try?

Ask yourself in a low voice: What do you think?

Say and say:

5+6= 1 1 What do you think?

Think about it: 6 plus 5 equals 1 1, and 5 plus 6 equals 1 1.

4+7= 1 1 What do you think?

Think about it: 7 plus 4 equals 1 1, and 4 plus 7 equals 1 1.

Ask each other in pairs about 3+8= 1 1 and 2+9= 1 1.

Consolidate and improve

1, do one and two questions on page 95 of the textbook.

Students finish independently, teachers patrol, students discuss at the same table after finishing, and talk about your calculation method.

2. Complete Exercise 22 in the textbook, Question 2.

Students finish independently, teachers patrol, discuss in the group after completion, and then the representatives of the group members tell the answers, and the teachers confirm the answers after comments.

3. Complete Exercise 22, Question 3 in the textbook.

Students do it independently and teachers patrol. After the completion, the students tell the answers in the form of group representatives, see which group is right and fast, and judge the winning group.

Summary after class

In this lesson, we learned how to calculate the addend of 5, 4, 3 and 2. This question is different from the 9, 8, 7 and 6 addends we learned before. The previous problem is that the addition of big corner decimal, 0.5, 4, 3 and 2 is calculated by exchanging the addend position and thinking about big corner decimal. Today, the students did well and taught themselves 5 with what they had learned.

Write on the blackboard.

Add a few words to the third, fifth, fourth, third and second sections.

5+7= 5+8=

Thinking: 7+5= 12 thinking: 8+5= 13.

5+7= 12 5+8= 13

The position of the commutative addend is calculated by Osuka decimal.