Teaching plan of four operations of mathematics in the second volume of the fourth grade of People's Education Press I. Unit teaching content
Four operations P2P 12
Second, the unit teaching objectives
1, knowing addition, subtraction, multiplication and division is called four operations.
2, combined with the real life situation, can actively explore and understand the operation sequence including two-level operation, and can correctly calculate the two or three-step problem.
3. Grasp the characteristics of 0, and know that 0 is inseparable during the operation.
4. Let students feel some strategies and methods to solve problems in the process of exploration and communication, and learn to solve some practical problems with two or three different calculation methods.
5. In the process of solving practical problems, let students cultivate their awareness of estimation and develop study habits such as careful examination of questions and independent thinking.
Third, unit teaching is heavy and difficult.
Key points:
1. Understand the meaning of the four operations and master the operation order of the four operations.
2, can correctly calculate the two or three steps.
3. Be able to solve simple practical problems reasonably and master the strategies and methods to solve problems.
Difficulties:
1, accurately calculate the two or three-step problem.
2, can list the correct comprehensive plan to solve practical problems.
3. Understand that 0 is not divisible.
Fourth, the unit teaching arrangement
Four operations; 6 class hours
The significance of addition and subtraction in lesson 1 and the relationship between the parts.
First, the teaching content: the significance of addition and subtraction and the relationship between the parts P2P3
Second, the teaching objectives:
1, through observation and comparison, further understand the meaning of addition and subtraction, and master the relationship between addition and subtraction.
2. Cultivate students' ability of comparison, generalization, induction, judgment and reasoning in the process of discovering the relationship between addition, subtraction, multiplication and division.
3. Use the relationship of addition and subtraction to solve simple practical problems.
Third, teaching focuses on difficulties.
Key points: further understand the significance of addition and subtraction, and master the relationship between addition and subtraction.
Difficulties: Understand and master the reciprocal relationship of addition and subtraction.
Fourth, teaching preparation.
Physical projection, courseware
Teaching process of verbs (abbreviation of verb)
(A) the introduction of new grants
Addition and subtraction are good friends. What's the secret between them? Today, we will learn the meaning of addition and subtraction and the relationship between the parts. Write on the blackboard.
(2) Exploration and discovery
1, and discuss the significance of addition and subtraction.
The Significance of (1) Teaching Addition
Show the theme map of P2 case 1.
Thinking: How to find out how many kilometers the railway from Xining to Lhasa is? How to calculate? Can you express the relationship between them by line drawing?
After students think independently, they can make an independent formula: 814+142 =1956 (km) and show the line chart.
Combined with the addition formula, talk about the significance of the addition formula.
The teacher summed up: the operation of synthesizing two numbers into one number is called addition.
Do you know the name of the addition part?
The teacher summed up: the sum of two numbers is called addend, and the added number is called sum.
(2) the significance of subtraction teaching
Courseware shows P3 case 1(2)(3)
Students independently analyze the quantitative relationship, calculate in parallel, and try to draw line segments independently.
After the board is named, talk about why subtraction is used.
Summary: How many kilometers does the railway from Golmud to Lhasa need? The railway length from Xining to Golmud should be excluded from the total railway length from Xining to Lhasa. And how many kilometers is the railway from Xining to Golmud? It is necessary to remove the length of the railway from Golmud to Lhasa.
Please observe the relationship between the above two questions and the previous question (1).
Summary: The question (1) is actually two known numbers. Find the sum of them and add them up. Problems (2) and (3) are to know the sum of two numbers, add one of them, find the other addend and do subtraction.
Think about it: What kind of operation is subtraction?
Summary: Given the sum of two numbers and one addend, the operation of finding the other addend is called subtraction. The sum known in subtraction is called the minuend, in which one addend is called subtraction and the other addend is called difference.
2. Explore the relationship between addition and subtraction.
Can you talk about the relationship between addition and subtraction?
After group discussion, report and exchange, and the teacher writes on the blackboard.
What do you think is the relationship between addition and subtraction? Summarize in one sentence.
The teacher summed up: subtraction is the inverse operation of addition.
(3) Consolidate differences
1. According to the addition and subtraction relationship, write two subtraction formulas corresponding to the following formulas.
125+346=47 1
34+595=629
654+528= 1 182
2. Complete P3 independently and tell me what you think.
(4) Evaluation feedback
Tell me what you got.
(5) Blackboard design
The significance of addition and subtraction and the relationship between the parts.
814+1142 =1956 (km)1956-142 = 814 (.
1956-814 =1142 (km)
Addition: the operation of combining two numbers into one number. Subtraction: the operation of finding another addend by knowing the sum of two numbers and one of them.
Sum = tooth tip+tooth tip difference = minus-minus.
Appendix = sum-another appendix minus = minus-difference.