The textbook of this lesson first lists the tables of carry addition within 20, and then guides students to observe the arrangement law of carry addition within 20 in the form of questions to help students further master the calculation method of carry addition within 20. A "math game" is arranged below, which requires students to find a calculation card according to numbers, so that students can further skillfully calculate carry addition within 20, and at the same time develop their reverse thinking. Then exercise 22 and various forms of exercises.
The design concept of the textbook mainly highlights the following three aspects: first, systematically combing the carry addition within 20, infiltrating the method of knowledge combing and review. Secondly, in the learning activities of observing and analyzing tables and discovering laws, students' ability of analysis and generalization is cultivated. Third, make full use of the 20-decimal addition table to practice.
According to the above analysis, the following goals are set: in the game, review the calculation of carry addition within 20.
Through self-help and group cooperation, learn to review carry addition within 20 minutes and experience the process of sorting out knowledge.
Cultivate cooperative consciousness and methods. Cultivate the ability to evaluate yourself and others, infiltrate the thought of function, and cultivate students' divergent thinking and ability to solve multiple problems in practice.
Second, the teaching situation boutique fragments and analysis:
Situation 1:
Lottery game:
Teacher: What festival was it yesterday, children? The teacher did not come yesterday. In fact, the teacher prepared some math gifts for the children. Who touches them, what will you get?
Activity: Students draw formula cards from the gift box, do oral calculations, choose two or three difficult problems, and talk about how you do it. Let the students take a formula and put it on the physical projection.
It is children's nature to love playing and playing, especially for children in lower grades. Creating a lively and interesting learning environment is beneficial to children's learning. Therefore, the introduction of the situation of sending Christmas gifts is created, which can arouse students' strong interest and produce positive learning emotions. The children all want to draw a card gift from the box to calculate, so that the original boring oral calculation becomes interesting, fun and willing to accept. In the children's active study, they practice and consolidate the methods of addition and oral calculation within 20, which also makes them feel that oral calculation practice is also very interesting. ]
Situation 2:
Teacher: The formulas just calculated by the children are all carry addition within 20. In fact, what are the carry additions within 20?
Health: A lot.
{The teacher grabbed one and put it on the physical projection}
Teacher: How do you feel when so many formulas are put together?
Health: It's a mess.
Teacher: What should I do?
Health: tidy up.
Teacher: What a great idea! So if you do, what are you going to do
Teachers are organizers and guides of mathematics learning. The task of teachers is not simply to let students remember a certain method, but to create conditions for students to face a certain problem and experience a certain fact. Therefore, after the last link, it is natural to create a chaotic situation in which many formulas are put together, so that students can find problems independently and experience the necessity of knowledge collation, and children's interest is also sprouting in the process of experiencing facts. ]
Third, teaching highlights and analysis
Activity design 1
Discuss the swing.
Health 1: Sort by number.
Health 2: Sort by 9 plus a few, 8 plus a few and 7 plus a few.
2. Teacher: After listening to so many ideas, do you want to sort them out yourself?
Health: Yes.
Teacher: Teacher Nana has prepared recipe cards for the children. The children gently took it out, put it on the table and put it on. Remember, there are only 8 minutes, and the fastest team will get a star. Let's go
3. Students operate and teachers patrol.
"Mathematics Curriculum Standards" points out: "Effective mathematics learning activities can not only rely on imitation and memory. Hands-on practice, independent exploration and cooperative communication are important ways for students to learn mathematics. " In this link, the teacher does not simply take out the tables in the book for the students to observe, but fully lets the students sort out their own addition tables within 20 in the exchange, discussion and cooperation. Students have gone through a process of systematic arrangement and review, which not only deepens their understanding of knowledge, but also preliminarily perceives the methods of review and arrangement. ]
Activity design 2:
Show students' works and evaluate communication:
(1) Teacher: Which group of children would like to introduce their works?
Activity: Students introduce a group of their own works, and teachers give in-depth guidance according to the students' situation. Such as: why and equal? Infiltrate one addend, the other addend is greater than one, and the sum is greater than one; One addend is less than one, the other addend is greater than one, and the sum remains the same.
(2) Teacher: Now we don't introduce ourselves. Let's talk about other groups. Which group do you like best and why? (Let students discover different group rules from themselves)
(3) Teacher: The teacher found that several groups were not finished. Why didn't your team finish? (The importance of infiltration and cooperation) If their arrangement is regular, Q: Guess what they will do next? Why do you think so?
[In this link, the teacher is always in the position of a guide, guiding students through the evaluation of students, not only exchanging sorting methods, but also cultivating students' observation ability, and infiltrating the importance of cooperation in a timely manner. In the analysis table, through the teacher's appropriate questioning guidance, the idea of function was initially infiltrated. In the process of evaluation and communication, students can really gain something and think. ]
Third, practice designing high-quality fragments and analysis.
Practice design 1:
Answer the first game:
1, teachers and students scrambled to answer.
The teacher refers to the formula and the students answer first.
2. Answer the questions.
Group, one person counts, the other three people answer first, and then take turns.
[This quick answer game combines the table rules compiled in this lesson with the calculation of carry addition within 20, and stimulates children's interest in learning in the form of games, so that children can better consolidate their knowledge and learn to apply. Moreover, this game can feed back the learning effect of students in this class, master the law of this form, and let teachers adjust the teaching links in time. ]
Exercise design 2:
Textbook 1 12 Page "Mathematical Games":
The teacher reported a number, and the students found the calculation card according to the number. Tell me what you think.
Compared with the last exercise, this exercise is more challenging in thinking. Through this exercise, students not only skillfully calculated the addition within 20, but also re-applied the rules of tables, which developed students' reverse thinking. ]
Exercise design 3:
Take a maze:
1, Teacher: What a clever boy! Just sorting out and reviewing so many formulas (blackboard writing: sorting out and reviewing) and putting out an image staircase. Actually, this picture is quite interesting. Do the children want to play?
Let's play the game of walking the maze. The entrance to the maze is here. The requirement is that we take more formulas than each one 1. Can you get out of the maze? Discuss in groups, how are you going to go, and then draw a picture on the table you made up.
2. Group cooperation
3. Report
Especially for low-level children, interest is the direct driving force of their creativity and the premise of creative thinking. In practice, teachers try their best to tap the potential of teaching materials and carefully design maze-walking exercises full of childlike interest, so that students can acquire knowledge in a pleasant atmosphere. Such a multi-solution exercise is conducive to stimulating students' curiosity and making classroom teaching full of vitality. Students are not passive recipients of knowledge but active discoverers and researchers. Students no longer study mathematics, but do it, which promotes the development of students' divergent thinking and comprehensive ability.