Lecture notes on "addition and subtraction of decimals" in elementary mathematics

As a selfless teacher, it is often necessary to prepare speeches, which can improve the teaching quality and achieve good teaching results. How to write the speech? The following is the model essay of the lecture draft of "Decimal Addition and Subtraction" in elementary mathematics that I compiled for you. I hope it helps you.

First of all, talk about textbooks.

The design concept of this course is to combine mathematics with solving practical problems in life, make full use of shopping materials, guide students to find and ask questions from real situations, and make use of students' existing experience to make students fully perceive and experience decimal addition and subtraction with the same number of digits in independent inquiry, operation and communication, actively construct new calculation methods, and experience the wide application of decimal addition and subtraction in life. Cultivate students' ability to explore mathematics knowledge independently.

Teaching objectives:

1, combined with the specific situation, explore and master the calculation method of decimal addition and subtraction, and can calculate correctly.

2. Decimal addition and subtraction can be used to solve some practical problems and improve the ability of analyzing and solving problems.

3. Let students gain a successful experience in exploration and enhance their confidence in learning mathematics.

(B) Teaching focus: the calculation rules of decimal addition and subtraction

Take the shopping problem as an example. When the currency is written in yuan, the percentile indicates the point and the decimal indicates the angle, which is convenient for students to understand and master. Create a situation that is closely related to the reality of life, so that students can obtain the written calculation method of decimal addition and subtraction through their own exploration and cooperation.

(c) Teaching difficulty: Understand the principle of decimal point alignment when columns are vertical.

Because students have the basis of integer addition and subtraction and a decimal addition and subtraction (they don't abdicate), they make full use of this knowledge and experience in teaching, ask questions and solve problems. In this series of learning activities, the teacher doesn't give any hints to the students, but reminds them to solve problems according to their existing experience, try to write vertically in decimal addition and subtraction, and realize the calculation method of decimal addition and subtraction in exploration. At the same time, through the exchange activities between teachers, students and students, the preliminary understanding will be raised to a new height, and the general methods of decimal addition and subtraction will be summarized to further understand the principle of decimal point alignment when columns are vertical.

(d) New knowledge: calculation rules of decimal addition and subtraction.

(5) The breakthrough point of moral education: Books are the ladder of human progress.

(6) The position and function of teaching content in the whole textbook and a unit. ;

The second unit arranges the teaching content of "decimal addition and subtraction" Students have just finished learning decimals in Unit 1 of this textbook, mastered the meaning and nature of decimals, and arranged their study on the basis of a certain perceptual knowledge of addition and subtraction (not abdication) of a decimal. The textbook is divided into two levels. The first level studies the meaning of decimal addition and subtraction and the calculation rules of decimal addition and subtraction. The second level is to learn decimal addition and subtraction with different decimal places. This lesson is the first lesson at the first level of study, and it is the need of students' daily life and further study and research. Understanding and mastering the arithmetic of decimal addition and subtraction (that is, only numbers with the same counting unit can be added and subtracted) and algorithms (that is, aligning the same number of digits, that is, aligning decimal points) are the key to learning decimal addition and subtraction with different decimal places, and are basic and necessary mathematical knowledge, skills and methods.

Second, talk about teaching design

(1) Import link

Courseware shows the situation map, and books are the ladder of human progress. It teaches students to read more books and take care of them, and it also shows that there are many math problems worth studying.

New course links

This link first leads to the exploration of decimal addition calculation method: let students ask mathematical problems according to the picture information, can they try to solve these problems with what they have learned? Let the students try to calculate and experience the cognitive process. Through reporting and communication, the calculation rules of decimal addition and subtraction are preliminarily summarized.

(1) present information and ask questions.

Courseware shows the price of extracurricular books.

Fairy tale: 6.62 yuan; The Story of the Scientist: 2.75 yuan.

What mathematical information does the teacher ask the students to find? What math questions would you ask? Let the students ask questions.

Teacher's screening (presentation) problem, teacher: Let's solve the problem of "how much are these two books?"

The design is intended to create a price situation for extracurricular books close to students' lives for teachers, and students can ask questions independently. According to the questions compiled by students, the teacher grasps the questions in time and leads to the addition and subtraction of decimals. In this way, the teaching materials can be used flexibly, and at the same time, students can realize that mathematics knowledge comes from life and stimulate their enthusiasm for learning.

● Decimal addition:

It is easier for students to list formulas, and teachers guide students to explore calculation methods.

(2) Independent exploration and discovery methods.

(1) try independently. Teacher: Are there any different ways to solve this problem? Then choose a method you like to answer. After doing it, you can communicate in the group (or with your deskmate). The teacher patrolled and guided.

Design intention This is a preset question. Students can find different solutions through previous studies, such as estimation, oral calculation and pen calculation, so as to stimulate students' desire to explore new knowledge.

2 report and communicate.

A, what is the estimated total price of these two books? Praising students with estimation consciousness in time and seizing the opportunity is to strengthen the cultivation of students' estimation consciousness.

B, 6 yuan 6 Angle 2 points +2 yuan 7 Angle 5 points =9 yuan 3 Angle 7 points

C. The vertical calculation is 6.62+2.75=9.37 (yuan).

Most students choose to use vertical calculation, one student reports and the teacher writes on the blackboard.

Seize the opportunity to ask questions through students' oral calculation methods. (Q: How to align vertical writing? Why do you want this counterpoint? Why can decimal points be aligned and added directly? ) so as to solve the difficulties in class and understand the principle of decimal point alignment when the columns are vertical. When decimal points are aligned, the same digits are aligned, and the digits on the same digits can be added.

Observe the whole vertical process together after dictation: then describe the calculation method of decimal addition completely.

Grasp three points: ① Align the decimal point; ② Add the lowest digit; (3) to ten directions.

Decimal subtraction: solving the problem "How much is fairy tale more expensive than scientist's story? "After the column, use vertical calculation directly? Students do it independently. The teacher patrolled and guided. Ask the students to talk about their thoughts during the review.

Let the students imitate the addition operation, and compare and summarize it.

The design intention is that students have the knowledge of integer addition, subtraction and decimal addition to pave the way, so they dare to let them try. Through the space of students' independent exploration and cooperation, we can further understand the truth of "decimal point alignment" in the process of communication.

(3) Guide and summarize the calculation methods of decimal addition and subtraction.

The Guide concludes that when calculating decimal addition and subtraction, the numbers on the same digit should be aligned, that is, the decimal points should be aligned.

(4) Calculation method of decimal addition and subtraction when reading 36 pages.

(3) Expanding exercises:

1. Longitudinal calculation is 4.37+2.93 7.54+6.84.

The purpose of design intention exercise is to consolidate the algorithm and expose new cognitive conflicts. There is a "0" at the end of the calculation result, so handle the problem of "0" correctly. Students find problems and propose solutions. According to the nature of decimals, teachers guide students to correctly understand and master the simplification when there is "0" at the end of calculation results, that is, cross out "0" at the end.

To solve practical problems

Courseware demonstration

The design aims to solve the problems around us and realize that new knowledge comes from life and serves life. In solving problems, students can further understand the significance of decimal addition and subtraction, correctly calculate decimal addition and subtraction and master new skills.

(4), class summary:

It is divided into two parts: first, read 36 pages and sort out what you have learned; Then the students talk about their gains and experiences. Summarize whether the predetermined knowledge and emotional goals have been achieved.