Simple decimal addition and subtraction teaching plan 1 teaching content
Simple addition and subtraction of decimals (page 96 of the textbook and related contents).
Teaching objectives
1. In specific cases, we realize that the meaning of decimal addition and subtraction is the same as that of integer addition and subtraction.
2. After exploring the calculation method of decimal addition and subtraction, decimal addition and subtraction will be calculated correctly.
3. According to the created real life situation, flexibly use the relevant knowledge of decimals to solve practical problems and cultivate application awareness.
Important and difficult
1, master the calculation rules of decimal addition and subtraction.
2. Correct calculation of decimal addition and subtraction with different decimal places.
Teaching process:
Import scene
1, the teacher said: We have learned integer addition and subtraction before, so how to calculate integer addition and subtraction? Let's recall that the teacher has two questions here and invited two students to do them. Other students think about three questions while watching their calculation process:
① What should I pay attention to when writing vertically?
(2) Which should I start with when calculating?
③ What should I pay attention to when calculating?
2, naming calculation: 48+9=, 25- 17=, teachers guide students to observe.
3. The feedback questions are correct, and three questions are answered by name.
4. Teacher's summary: Through practice, we know that when calculating integer addition and subtraction: ① The same numbers should be aligned and calculated from the low position. (2) If you add up 10, you will enter "1"; if you subtract less than, you will enter "1" and then subtract 10. This is the integer addition and subtraction I learned before, so how to calculate the decimal addition and subtraction? Today I invite you to learn the addition and subtraction of simple decimals.
Blackboard writing: addition and subtraction of simple decimals
New course teaching
1, ask questions and list formulas by using the theme map.
(1) Show the theme map. Guide the students to observe and ask questions: Can you tell us what this picture tells us through observation? At the beginning of school, students go to the stationery store to buy school supplies, each blue notebook 2.5 yuan, each schoolbag 25.8 yuan, each pencil box 6.8 yuan ...)
(2) Using the obtained mathematical information, what questions can you ask? Can you make a formula? Guide the students to say the questions raised, one to say how to form them. The teacher wrote the formula said by the students on the blackboard. On the basis of students' parallel questions, the teacher leads to the theme: If a classmate buys a pencil sharpener and a green pencil, how many questions can we ask? What's the problem? How much is a pencil sharpener and a green pencil? How much is a pencil sharpener more expensive than a green pencil? How much is a green pencil cheaper than a pencil sharpener? After affirming their statement, the teacher asked, can you state it? (Students answer, the teacher writes on the blackboard) How to calculate the two questions "0.8+0.6=, 0.8-0.6="? Please come and study.
2. Students interactive inquiry "0.8+0.6=, 0.8-0.6=".
(1) Teacher: What are you going to do? Please try to calculate on the math homework paper and tell your deskmate what you think. Student activities, teachers patrol and exchange.
(2) Reporting feedback: There may be several situations: ① Students orally calculate the results, but let the students explain their ideas; (2) Rewrite 0.8 yuan and 0.6 yuan into 8 angles and 6 angles, add and subtract them, and then rewrite them into decimals with yuan as the unit; (3) Write a vertical form according to the integer addition and subtraction reviewed earlier.
Teacher summary blackboard writing:
0.8+0.6= 1.4 (yuan)
0.8-0.6=0.2 (Yuan)
A: Pencil Sharpener 1.4 yuan, Pencil Sharpener is more expensive than green pencil in 0.2 yuan.
The teacher asked and explained: Is the "8" and "0.8" the same here? Why? Therefore, when adding or subtracting decimals directly, you can also write units, elements and angles vertically to align the same number of digits, which is the same as integer addition and subtraction.
3. Students' interactive inquiry "1.2-0.6=".
(1) Teacher's guidance: Just now, a classmate asked how much a pencil with an eraser is more expensive than a green pencil. The formula is: 1.2-0.6=. Please try vertical calculation according to your own learning experience.
After the students finish, talk about different methods. The teacher summarizes them on the blackboard.
Method 1: take 1 as the angle of 10, add 2 angles, and subtract 6 angles from 12 to form 6 angles.
Method 2: 2 minus 6 is not enough. If you subtract 1 from its previous position, it is 10. If you add the original 2 to 12 and subtract 6 from 12, you get 6. Write below 6. If the preceding 0 is negative 0 or 0, you get 0.6.
(2) When you are calculating, how can you ensure that elements are subtracted from elements and angles are subtracted from each other? (Just align the decimal point)
4. Compare decimal addition and subtraction with integer addition and subtraction.
What are the similarities and differences between teachers and students when observing and reviewing the content of this lesson?
Same point: (1) Same digit alignment, counting from the lower digit.
(2) All decimal numbers are 1, and the return of 1 is ten.
Difference: When adding or subtracting decimals, as long as the decimal points are aligned, the same digits are aligned.
5. Guide the students to summarize: How to calculate the addition and subtraction of decimals?
Homework done in the classroom
Calculate:
0.8-0.5=
0.7+0.4=
1.6+2.3=
1.9- 1.3=
2.3-2.3=
5.3+ 1.6=
0.5+3. 1=
0.8+ 1.5=
3.6-0.6=
Course summary
Please tell me how to calculate the simple decimal addition and subtraction.
Homework after class
1, the textbook Exercise 2 1, page 98, questions 1, 2, 3 ".
2. Finish the exercise of the lesson "Hour by Hour".
Teaching blackboard:
Simple decimal addition and subtraction
Same digit alignment
0.8+0.6= 1.4 (yuan)
A: I used 1.4 yuan.
Decimal positioning
0.8-0.6=0.2 (Yuan)
A: Pencil sharpeners are more expensive than green pencils, 0.2 yuan.
Teaching reflection:
The content of this lesson is based on students' learning the meaning of integer addition and subtraction and the meaning and nature of decimal. "Mathematics Curriculum Standard" clearly points out: "Mathematics is closely related to life, and mathematics comes from life and serves life". In real life, many students have had experience and their own methods in decimal calculation when shopping, so they designed the scene of buying stationery in a stationery store and explored the calculation method of decimal addition and subtraction. Through shopping, let students find the math problems in their lives and find the ways to solve them through their own personal observation. By feeling life, let students know that mathematics is around and cultivate students' interest in learning mathematics. Teaching should be combined with specific teaching situations to help students understand the principle of decimal point alignment and pay attention to cultivating students' ability of generalization, induction, analysis and application.
Simple decimal addition and subtraction teaching plan 2 teaching goal
1, master the calculation method of decimal addition and subtraction.
2. Encourage students to use various methods to calculate decimal addition and subtraction, so as to solve practical problems and realize and understand decimal addition and subtraction.
Emphasis and difficulty in teaching
Key points: you can correctly calculate the addition and subtraction of one digit after the decimal point, and know that the decimal point alignment is the same digit alignment.
Difficulties: experience the arithmetic in the calculation process and deepen the understanding of the calculation method of decimal addition and subtraction.
Teaching preparation
courseware
teaching process
First, pre-school preparation
1, let the students say how you do integer addition and subtraction.
2. Write the following questions.
32+54= 68-7= 48+9= 25- 17=
According to the calculation of these four questions, what are the characteristics of these four questions? (The first two are integer addition and subtraction, and there is no need to carry or abdicate; For the third addition problem, the digits from ten to ten add up to "1", and the decimal digits should be added with "1"; If the number of digits in the fourth subtraction problem is not enough, you need to subtract "1" from the tenth digit and then subtract it together, and don't forget to subtract "1" from the tenth digit.
3. Teacher: ① When adding and subtracting integers, the same digits should be aligned and added and subtracted from single digits. (2) Which one adds up to ten to change the previous one into 1, and which one is not enough to reduce the previous one back to 1.
Second, explore new knowledge.
1, example 3 on page 96 of the study textbook (1).
Show the theme map of the textbook. The teacher asked: Can you tell us what the map tells us through observation? According to the students' answers, the teacher leads to the topic. If a classmate buys a pencil sharpener and pencil, what questions can we ask? After the teacher affirmed their statement, he asked, can you state it? (Students answer, the teacher writes it on the blackboard)
0.8+0.6=? 0.8-0.6=
The teacher organizes students to discuss and say what you think. What do you want to do?
There may be several situations: ① Students can calculate the results orally, but let them explain their ideas. (2) Rewrite 0.8 yuan into 8 corners, 0.6 yuan into 6 corners, and then rewrite it into decimal places with yuan as the unit after addition and subtraction. ③ Write vertical calculation according to the integer addition and subtraction reviewed earlier.
Teachers combine books on the blackboard;
0.8+0.6= 1.4 (yuan)
Method 1: 8 Angle Method 2: Yuan Angle
+6 cents? 0.8
? 1 yuan 4 jiao +0.6
1.4
A: A *** 1.4 yuan.
? 0.8-0.6=0.2 (Yuan)
Method 1: 8 Angle Method 2: Yuan Angle
Six cents? 0.8
2 degree angle -0.6 degree
0.2
A: Pencil sharpeners are more expensive than pencils, 0.2 yuan.
Teacher's explanation: When adding and subtracting directly with decimals, you can also write units on vertical type. In order to align the same numbers, this is the same as adding and subtracting integers.
2. Study Example 3(2).
Teacher's guidance: If we ask how much the pencil with eraser is more expensive than the pencil without eraser, how to arrange it?
Students can try to do it by themselves according to the experience of Example 3( 1). After the students finish, talk about their different practices.
Third, the design of new classroom assignments
1. Calculate the following problem vertically.
2.4+4.9= 6.5+0.8= 5.2-0.7= 4. 1-3.3=
2. Write vertically and count.
? 4.8+5.6 5.6-4.8 5.6+5.2 5.6-5.2
Fourth, thinking training.
1, a number written directly.
? 0.8-0.5= 0.7+0.4= 1.6+2.3= 1.9- 1.3=
? 2.3-.3= 5.3+ 1.6= 0.5+3. 1= 0.8+ 1.5=
2. Try it with your head.
7.□ 6.□
-□.3 +□.5
3.5 13.3
Notes on blackboard writing
Simple decimal addition and subtraction teaching plan 3 design instructions
1. Close contact with life, so that students can learn effectively in familiar situations.
Real life is the starting point and destination of learning mathematics. In real life, many students already have the experience of decimal calculation and their own methods when shopping. Therefore, the situation of stationery shop shopping is designed in teaching. By leading students to visit and buy stationery, * * * explores the calculation method of decimal addition and subtraction. Through shopping, let the students find the mathematical problems in life, and through their own observation, find the ways and means to solve the problems.
2. Pay attention to the guidance of learning process and learning methods and strategies.
This design first guides students to ask their own questions, and then gives them sufficient thinking space, prompting them to try to solve problems according to their existing experience, not only to find reasons and basis for their own methods, but also to verify the explored calculation methods. In this process, students get the promotion of thinking methods and positive emotional experience, which really allows students to enjoy learning and thinking.
Preparation before class
Teacher prepares PPT courseware, supermarket shopping receipt.
teaching process
Introduce dialogue to stimulate interest
Teacher: Students, do you often go shopping in the supermarket? What did you buy?
Teacher: Today, the teacher will take the students to the stationery store in Math Paradise. Let's have a look! (Courseware shows the theme map of stationery shelves)
Teacher: Watch carefully and see what you can find. Teachers guide students to exchange information and tell the names and prices of goods through observation. )
Teacher: The students watched carefully. Can you ask some questions according to the mathematical information you see?
Design intention: present the shopping situation, guide students to ask questions through observation, cultivate students' consciousness of careful observation and good at asking questions, and effectively stimulate students' desire to explore new knowledge.
Explore new knowledge
1. Example 3 is a 96-page textbook.
(1) Ask questions.
Teacher: According to the information the students have just seen, can you ask math questions according to these two stationery in the courseware? (Courseware shows pencil sharpener and ordinary pencil)
preinstall
1 Pencil Sharpener and 1 How much are ordinary pencils?
1 How much is the pencil sharpener more expensive than 1 ordinary pencil?
1 How much is the ordinary pencil cheaper than 1 pencil sharpener?
(2) Introduce the theme.
Teacher: How are these questions worked out? (The first one is calculated by addition, and the last two are calculated by subtraction)
Teacher: What are 0.8 and 0.6? (decimal)
Teacher: This is the "simple decimal addition and subtraction" we are going to learn next.
(3) List the formulas and discuss the calculation methods in groups.
The teacher made a tour to understand the students' discussion.
(4) Collective feedback.
Teachers guide students to start from their own actual situation and find solutions suitable for their knowledge level. There may be two calculation methods among students. One method is to rewrite the amount of money into an integer with the unit of "angle" for calculation, and the other method is to add and subtract decimals directly.
(5) Guide students to report.
One is to rewrite "yuan" as "angle" and convert decimal addition and subtraction into integer addition and subtraction for calculation, that is, 8 angle +6 angle and 8 angle -6 angle.
The second is addition and subtraction in yuan, which is decimal addition and subtraction, namely 0.8+0.6 and 0.8-0.6.
(6) Students try to calculate 0.8+0.6 and 0.8-0.6 manually.
Before the students do the written calculation, the teacher first discusses the problem of number alignment with the students and demonstrates it. Guide students to say what to do first, then what to do, and finally what to do when calculating 0.8+0.6 vertically.
Observation and thinking: In addition and subtraction of decimals, what alignment is needed for the numbers on the same digit? (decimal point alignment)
(7) Question: We can calculate 0.8+0.6. Can you work out 0.8-0.6? (Students communicate with their deskmates after thinking independently, and then report)
(8) Feedback exercise: 2.8+2.16.4-0.9 4.7+5.3 5.6-5.3.
When revising collectively, the key points are: can the zero and decimal points in front of the numbers not be written?
2. Guide students to discuss and summarize the calculation methods of decimal addition and subtraction.
Teacher: first align the decimal points (that is, align the same numbers), and then calculate according to the calculation method of integer addition and subtraction. The decimal point of the obtained number should be aligned with the decimal point in the formula.
3. According to the above method, solve the problem that 1 with rubber pencil is more expensive than 1 ordinary pencil. [Self-determination, 1.2-0.6 = 0.6 (yuan)]
4. Experience the similarities and differences between decimal and integer addition and subtraction.
Teacher: How is the calculation method of decimal addition and subtraction the same as integer addition and subtraction? What is the difference?
Students discuss on the blackboard: the same point: integer addition and subtraction, decimal addition and subtraction are the addition and subtraction of numbers on the same digit; Require counting from the low position; They are all above 10, and enter 1 and retreat 1 to 10. Difference: integer addition and subtraction are aligned with the last digit, decimal addition and subtraction are aligned with decimal point)
Design intention: On the basis of solving the problem, deepen students' understanding that the same digit alignment is decimal point alignment in calculation, and use 0 to occupy a position, so that students can master the vertical calculation method of decimal addition and subtraction.
5. Example 4 is a 97-page textbook.
(1) Please help the teacher solve another practical problem. Xiao Liyou 10 yuan bought a pencil case of 1 and wanted to buy a notebook of 1 and a pencil of 1. Does she have enough money? If I change the ordinary pencil into a pencil with an eraser, will the money be enough?
(2) Guide students to discuss, analyze, solve problems and report methods.
preinstall
Method 1: After buying 1 pencil case, the remaining 10-6.8 = 3.2 yuan.
Then it is calculated that it takes 2.5+0.6 = 3. 1 (yuan) to buy a notebook with 1 and a pencil with1.
Because 3.23. 1, the money is enough.
If the ordinary pencil is replaced by a pencil with eraser, it will cost 2.5+ 1 notebook and 1 pencil with eraser * * = 3.7 yuan, because it is 3.73.2, so the money is not enough.
The second method is to calculate the remaining 1 0-6.8 = 3.2 yuan after buying1pencil case.
Calculate and buy a notebook of 1, and 3.2-2.5 = 0.7 (yuan). 0.70.6, 1 ordinary pencil is enough; 0.7 1.2, it is not enough to buy 1 pencils with erasers.
Method 3: Add up all the prices of the items to be bought to see whether it is greater than 10 yuan or less than 10 yuan.
6. Complete "Doing" on page 97 of the textbook.
Design intention: Use your own shopping situation to guide students to understand arithmetic and query algorithms, give students time to explore independently, fully communicate and enjoy, better let students experience the query process, and highlight the teaching focus of understanding arithmetic and query algorithms. At the same time, in the process of solving practical problems, students are guided to use a variety of strategies to solve problems, which reflects the diversity of problem-solving strategies.
Decimal addition and subtraction simple teaching plan 4 teaching objectives:
1. Understand the meaning of decimal addition and subtraction, and master the calculation method.
2. Students can skillfully write decimal addition and subtraction,
3. Cultivate students' abstract generalization ability and transfer analogy ability.
Teaching process:
First, scene import
1, Teacher: "Fenxiang Stationery Supermarket" has opened. Let's go and have a look!
(1) Show the theme map: Look at the picture. What product information do you get from the map? (Name)
(2) The boss said that all stationery will be sold at low prices during the opening period, so everyone can only choose two kinds. Think about it: What do you want to buy most? Try to figure out how much you should pay.
(3) Try to calculate. Then say, which two are you going to buy? How much is a * * *?
The teacher writes on the blackboard according to the students' answers.
3. Say and write on the blackboard.
Second, explore the experience
1, learn decimal addition
(1) How do you calculate the price of the stationery you want to buy most?
(2) Health report exchange, the teacher writes on the blackboard.
(3) Teacher-student summary: Decimal addition, like the previous addition, is also the operation of combining two numbers into one number.
(4) Guide students to sum up: What are the similarities between decimal addition and previous addition in calculation? How to calculate the fractional addition?
(5) Observation and thinking: How to align the numbers with the same number in decimal addition?
(6) Guide students to compare the two types. Based on their actual learning situation, students look for solutions suitable for their knowledge level.
2. Learn decimal subtraction
(1) Dialogue Introduction Example 4 Ask a question: Can you solve this problem? How should it be formulated?
(2) Organize students to discuss: How to make a column and calculate the numbers correctly?
(3) Guide students to talk about why decimal points of decimal subtraction should be aligned.
(4) How to calculate this vertical type? Students try, teachers patrol and guide.
(5) Guide students to talk about the process of vertical calculation 1.2-0.6.
(6) Teacher-student summary: the calculation method of decimal subtraction.
3. Guide the students to discuss and summarize the calculation methods of decimal addition and subtraction: Let the students make it clear that the addition and subtraction of numbers on the same digit all start from the lowest place, and all are "full ten into one" or "back one into ten". Only the decimal points of decimal addition and subtraction are aligned, and the same numbers are aligned.
Third, practical application.
1. Complete "Done" on page 96.
2. Complete Exercise 22, Question 1 (written in the textbook, allowing individual students to count vertically).
3. Using Mathematics: Exercise 22, Problem 2, students can solve independently.
Fourth, the class summary
1. What new knowledge have you learned through today's study?
2. Teacher's summary.
Simple teaching design of decimal addition and subtraction
* * * A total of 5 class hours, class 50.
Teaching objectives:
1, through practice, further understand the meaning of decimal addition and subtraction and the calculation method of decimal addition and subtraction. Let students write decimal addition and subtraction skillfully.
2. Further cultivate students' ability of abstract generalization, analysis and problem solving.
Teaching process:
First, check the import.
1, I will calculate. (Complete question 3 on page 97)
(1) Measure the height before class.
(2) Tell each other your height at the same table and write it down.
(3) Complete the third question independently.
(4) report and communicate by name. Help evaluate and revise for the rest of my life.
2, talk about import, blackboard writing topic.
Second, explore the experience
1, complete question 4 on page 97.
(1) Look at the pictures and read the questions, and make clear the meaning of the questions.
(2) Ask questions by name and write them on the blackboard.
(3) Students independently complete the blackboard writing problem.
(4) The whole class reports and exchanges, explaining and correcting.
2. Complete question 5 on page 98.
(1) Retell the meaning of the question by name after reading it.
(2) Discuss how to calculate in groups.
(3) the whole class reports and exchanges.
(4) Teacher-student summary method.
Third, practical application.
1. Students independently complete the sixth question on page P98.
(1) Look at the bar chart by name and tell the mathematical information.
(2) Independent formula calculation.
(3) Collective feedback and communication.
2. Students who have spare time to study can complete the thinking questions on page P98.
Fourth, the class summary
1. What did you get from today's exercise?
2. The teacher summed it up.
Simple teaching plan of decimal addition and subtraction 5. Teaching objectives
Knowledge and skills
Make students further understand the meaning of decimal in specific situations, understand the simple arithmetic of decimal addition and subtraction, and master the calculation method, which will correctly calculate the addition and subtraction of a decimal.
(2) Process and method
Make students experience the process of understanding arithmetic and exploring algorithms, and cultivate their ability of induction and knowledge transfer.
(3) Emotional attitudes and values
Let students feel the close connection between mathematics knowledge and real life.
Second, the importance and difficulty of teaching
Teaching emphasis: ① Understand the simple arithmetic of decimal addition and subtraction; ② Mastering the calculation method will correctly calculate the addition and subtraction of a decimal.
Teaching difficulty: understanding simple arithmetic of decimal addition and subtraction.
Third, teaching preparation.
Courseware, etc.
Fourth, the teaching process
(a) review of imports
1. Write down the following questions and talk about what should be paid attention to when calculating.
256 + 98 = 635 - 574 =
2. Talk and reveal the topic.
Students have mastered the written calculation method of integer addition and subtraction. How to calculate the addition and subtraction of decimals? Today we will learn the addition and subtraction of decimals together.
(blackboard writing: simple decimal addition and subtraction)
The design intention is to review written integers to introduce new lessons, introduce the old and promote the new, pave the way for students to feel the connection between written integer addition and subtraction and written decimal addition and subtraction, and stimulate students' desire to explore new knowledge.
(2) Explore new knowledge
1. Courseware gives the theme diagram of Example 3.
What mathematical information did you get from it? What meaningful math problems can you ask?
2. The teacher writes on the blackboard selectively.
Motherboard book: How much does it cost to buy a pencil sharpener and a pencil without an eraser?
How much is a pencil sharpener more expensive than a pencil without an eraser?
Books on the blackboard: How much is a schoolbag and a pencil box?
How much is the notebook more expensive than the exercise book?
……
3. Will you solve these problems? How to form (two problems of main board book)?
4. Name the students.
5. What method will you use to calculate?
6. Students try to solve problems independently before communicating with students in the group.
7. Name the students to report:
Student 1:
Answer: It takes 1.4 yuan to buy a pencil sharpener and a pencil without an eraser. A pencil sharpener is more expensive than a pencil without an eraser, 0.2 yuan.
Student 2:
Answer: It takes 1.4 yuan to buy a pencil sharpener and a pencil without an eraser. A pencil sharpener is more expensive than a pencil without an eraser, 0.2 yuan.
8. Are they right? Can you check it? Name the students to perform.