Teaching design of subtraction within 5
Teaching content: Learn the subtraction on page p26 and complete the corresponding "doing" and questions 3-5 on page 28.
Teaching requirements:
1, through observation, operation, demonstration and expression; Make students know the meaning of subtraction, know the "-"sign, read the subtraction formula correctly, and make students understand that there are many problems in life that need to be solved by subtraction.
2. Cultivate students' hands-on operation ability and language expression ability through students' operation and expression; Cultivating students to actively participate in mathematics activities and gain successful experience not only enhances students' confidence, but also goes through the calculation process of subtraction.
Teaching objectives:
1. Make students understand the meaning of subtraction, know the negative sign and read the subtraction formula.
The correct composition of the number within 2.5 can be subtracted, and the number will be filled in after the subtraction formula.
Teaching emphasis and difficulty: understand the meaning of subtraction and read the subtraction formula correctly.
Teaching aid preparation: teacher: subtraction courseware within 5 minutes. Physical CD, dictation card.
Health: Prepare 5 disks, 5 sticks, etc.
Teaching process:
1. Review old knowledge
1, fill in the numbers in sequence.
( ) 3 ( ) 5
2. Listen to the formula and say the numbers (or write the numbers)
2+3 1+3 1+4 2+2 4+ 1 3+ 1
We learned addition yesterday. Does anyone remember what addition means?
(Put the two parts together)
4. Teacher's summary: When we add numbers within 5, we don't need to count or look at pictures. The best way is to use the composition of numbers to calculate more simply.
Second, explore new knowledge.
1. Guide observation and perceive the significance of subtraction.
Let the students observe carefully through the courseware demonstration.
Talk to each other at the same table, talk about pictures and ideas, and then talk to the whole class.
A child has three red balloons and a blue balloon in his hand. There are four balloons. Suddenly, a blue balloon flew away. How many balloons are left in Xiao Peng's hand? )
Teacher: Like this, if you subtract one from four, that is, if you subtract a part from a number, you have to use subtraction.
The blackboard says: "-"
2. Learn the subtraction formula
How many numbers can four balloons represent? Write on the blackboard: 4
One flew away. How many places did it fly away from?
How many numbers can a balloon fly away? Blackboard: 1
If you fly away like this, remove it, or eat it, you must use subtraction.
Blackboard: 4- 1=
Q: What is 4- 1=? what do you think? Tell everyone what you think. Any different ideas? Please say something.
3. Divergent association
Teachers guide and inspire students to talk about other things in life that can be expressed by 4- 1
Third, consolidate development and learn to use subtraction to calculate numbers within 5.
Fourth, find friends to play games.
Let four students stand in front of the platform with the digital cards of 1, 2, 3 and 4, and the students of 10 are looking for friends with their calculation cards.
Verb (abbreviation for verb) consolidation exercise
1﹒ The courseware demonstrates the scene of "doing one thing" on page 26 for students to observe carefully.
(1) Ask some students to explain the meaning of the picture. (2) Calculate the formula according to the meaning of the picture.
The courseware demonstrates a 27-page scene diagram of "doing one thing". Let the students observe the diagram carefully, then explain the meaning of the diagram, and finally write down the numbers.
2. (question 2 on page 27) Draw a picture first, and then calculate the formula.
A: The teacher explained 1 picture step by step.
(1) Draw four flowers first and ask the students: How many flowers are these? How much can a number represent? Write on the blackboard: 4
(2) Cross out 1 flower with a dotted line and ask: Who knows what it means? Please guess.
(3) Cross out 1 flower with a dotted line, which means to remove it. Then, if it is removed, what method should be used to calculate it?
(4) 1 How many flowers have been removed? What number can be used to represent the removed 1 flower? Blackboard: 1
(5) Who can list the formulas according to the drawings?
Blackboard: 3-2 = 1
B: According to what you just said, can you explain the meaning of the next two pictures and list the formulas? Have a try. (Complete in groups of 4 people)
(1) Name-the meaning of naming
(2) Name the formula and tell me what you think? Any different ideas?
3. Students independently complete the third question "Do one thing" on page 27. Students daub and fill in the form, teachers patrol, correct problems in time when they find them, and then evaluate them collectively.
Sixth, consolidate feedback.
1, page 27 question 1 and 2.
(1) Let the students put on their own compact discs, and discuss and communicate in groups of four, so as to help and encourage the students who are not good at learning.
(2) After telling the pictures, each child writes the formula independently.
In the group, the group leader will organize everyone to evaluate and talk about whether the formula written by everyone meets the meaning of the question, what is wrong and what should be corrected.
Seven, after-class summary:
What did you learn in this class?
1. I will say the meaning expressed by a subtraction formula.
1. I learned to calculate the subtraction within 5. I also know how much is left after a number is subtracted. Calculate by subtraction.
8. Homework: Exercise 5, questions 2 and 4 on page 28, in the notebook.
blackboard-writing design
Subtraction within 5
The minus sign 4- 1 = 3 reads: 4 minus 1 equals 3.
Teaching reflection: the teaching content of this class is what students learn on the basis of addition in 5 minutes, but for children who have just entered school, their class habits have not yet formed, their self-control ability is poor, and interesting learning methods are needed. In the form of traveling by train, I strung together a series of questions and turned boring exercises into lively and interesting mathematical activities. Let students experience the problem in the problem situation and increase the direct experience. In practice, by indicating numbers with fingers, listing formulas on their own cardboard, communicating in groups and scrambling to answer questions, let each student move and get the mathematics knowledge they need.