1. Combined with the understanding of numbers, students can master the operation of adding a number to an integer ten and the corresponding subtraction.
2. Consolidate the concept of number composition. Infiltration subtraction is the inverse operation of addition and infiltrates additive commutative law.
3. Apply what you have learned to solve simple math problems.
course content
Textbook page 4 1.
Prepare teaching AIDS and learning tools
Simple animation courseware, dictation cards, sticks, etc. Related to example 10.
Teaching design
Review old knowledge and pave the way for new teaching.
Teachers and students practice the composition of numbers.
What is the sum of three tens and two?
What's the sum of five tens and eight?
How many tens and ones are there in 46?
How many tens and ones are there in 28?
Through the review of the part of "Composition of Numbers", it paves the way for the later study of "Integer ten plus one digit and its corresponding subtraction". ]
Learn new knowledge by creating situations.
1. Teachers create situations and use courseware for animation demonstration: (Narrator) Xiaoming likes to drink yogurt! Because Xiaoming has performed very well these days, his mother promised to take Xiaoming to the mall to buy yogurt. The courseware shows the scene where mom takes Xiaoming to the shopping center. ) The assistant aunt first gave her mother 30 bottles (30 bottles of yogurt are shown on the left side of the courseware), and then gave her two bottles of yogurt to Xiaoming (2 bottles of yogurt are shown on the right side of the courseware). Who can ask a math question?
Through courseware display, students are brought into vivid life situations and their interest in learning is stimulated. This kind of question is mainly for not binding students' thinking, encouraging them to think actively, and cultivating students' consciousness of thinking and asking questions frequently. ]
2. Solve 30+2.
The teacher praised the students for their brains and chose a question: How many bottles of yogurt did mom buy? How should I calculate it?
Students' oral statements and teachers' blackboard writing: 30+2 = 32.
Please tell the students what they think. Why do you want to use addition calculation?
Let the students look at the graphic formula on the big screen and let them understand why addition calculation is needed. Add 30 and 2 to calculate the result of 30+2, which is based on the composition of numbers within 100: 3 tens and 2 ones make up 32. ]
3. Solve 32-2.
The teacher asked: Now we know that mother bought 32 bottles of yogurt for Xiaoming. After Xiaoming drank two bottles, how many bottles were left? Ask the students to list the formulas and answer them orally. The teacher wrote on the blackboard: 32-2 = 30. Can you tell us how it is calculated?
Let the students know: Why do you want to do subtraction? Then, according to the meaning of subtraction, remove 2 from 32 and calculate the result of 32-2. You can know the composition of numbers. There are 3 10 and 2 1 in 32. If you remove 2 1, there are 3 10 left, which is 30; You can also think of it this way: subtraction is the inverse of addition. Three tens plus two add up to 32, 32 MINUS two ones, and the remaining three tens are 30. ]
4. Solve 2+30.
Teacher's blackboard writing: 2+30 =
Let the students think independently, and then express their opinions in groups of four. Finally, students express their opinions and communicate with the whole class.
[Students can use the meaning of addition to calculate, or exchange the positions of 30 and 2 to calculate, so that students can communicate in groups first, which not only gives every student a chance to speak, especially those who don't like to speak, but also shows that the algorithm can be diversified, so that students can learn from each other and promote each other through communication. ]
Consolidate exercises with practical operations.
1. Put it on the table, calculate it, and tell me how you worked it out.
A. the teacher put a stick on the physical exhibition platform. Let the students observe carefully, come up with the corresponding formula, and then enter the determinant calculation, and let the students talk about how to calculate.
Put five bundles first, then six bundles.
Put three bundles of five and take five more.
B. Put the stick away according to the teacher's description, and then list the corresponding formulas according to the operation.
Put eight first, then two bundles.
Put four bundles of four pieces first, and then take four bundles away.
The purpose of this design is to let students deepen their understanding of the calculation process of addition and subtraction through the operation of learning tools, cultivate their awareness of using learning tools to help them learn, and strengthen their hands-on operation ability. ]
2. Math game: Who eats corn first?
The teacher created a scene: mother bear took her baby bear to the grassland. Mother bear sets up the oven to bake the baby's favorite corn. Baby bear drools at the smell. I really want to eat sweet corn right away. But mother bear is not in a hurry. She asked her baby to use his brain. Whoever can find the same formula as the number before the corn can eat the corn first.
Bringing students into the game situation through interesting stories and practicing oral arithmetic through games can arouse students' enthusiasm to participate in learning and let the whole class participate in happy activities. Through this exercise, students' knowledge of this lesson can be tested. ]
A. Teacher and three students demonstrate: First, arrange 12 cards with formulas on the blackboard, and the teacher plays mother bear (judge). Each of the other three students chooses a card at a time. After the calculation, they will tell the teacher the result. If it is correct, the teacher will send a card with corn on it, and each person can choose four times. Whoever gets four cards first is the winner.
B. Students play games in groups, and teachers join groups with weak activity ability to participate in activities. After the game, give praise and encouragement to each group of students who can calculate quickly.
Feedback exercise
1. Oral calculation: See who can calculate accurately and quickly.
Students do the fifth question on page 43 of the book, and the time limit is 2 minutes. Students do the questions, the teacher time, and then collectively correct them, telling how 75-5 and 90+8 are done.
[Through the calculation of time, students' self-confidence can be improved, and the consolidation of new knowledge can be strengthened through the calculation process of saying two questions. ]
2. Do question 6 on page 43.
Here, the multimedia courseware is used to show the scene of two people talking in the textbook (3 teachers, 40 students, 45 bottles of mineral water enough? ), let the students express their opinions after reading it, what will they do if they encounter such problems at this time, and talk about their own ideas. Students who can use formulas can list formulas.
Make full use of modern equipment to create a situation for students' thinking, so that students' thinking can be linked with real life as much as possible, exercise students' thinking ability with real-life problems, and let students realize that there is mathematics everywhere in life. In order to make students have different development, students with better level can abstract the thinking process into mathematical formulas. ]
3. Fill in the numbers in order: Do the 7th question on page 43. Let the students observe the relationship between the numbers given by each group first, and then fill in the numbers after finding the rules. After doing this, let the students talk about their reasons, that is, the law between each group of numbers in the topic.
Through such observation and thinking, students' observation ability and preliminary logical judgment and reasoning ability are cultivated. ]
summary
Expert evaluation
The biggest feature of the teaching design of this course is that the teaching materials selected in this course are conventional mathematics classroom contents. It embodies the general teaching idea different from ordinary teaching, mainly in the following aspects:
1. Teachers use students' existing life experience to create situations in which students can ask mathematical questions, which conforms to the law of learning and understanding of middle and low grade students in primary schools and also embodies the spirit of "everyone learns valuable mathematics". At the same time, it also cultivates students' ability of observation, association and thinking.
2. Holding group discussion, so that every student has a full opportunity to express his opinions, which embodies the spirit of "promoting students' all-round development" and "facing all students", and also practices the mathematical concept that "independent inquiry and cooperative learning are important ways for students to learn mathematics". Among them, respecting students' independent choice cultivates students' self-confidence and embodies that students are the masters of learning.
3. Using operation to make students try to practice is a process of paying attention to "hands-on practice" and "letting students experience the process of abstracting practical problems into mathematical models and explaining and applying them", which follows the "psychological law of students learning mathematics".
4. The design of math games is conducive to "entertaining" and can arouse the enthusiasm of learning. Let students improve their knowledge and ability in a relaxed and happy atmosphere. In particular, teachers' ability to participate in group activities is weak, which reflects the role of teachers as "collaborators" in students' learning.
5. In practice, letting students tell different thinking processes reflects the learning method that attaches importance to the learning process, and encourages students who can use mathematical expressions to list formulas, which reflects the new teaching concept that "different people get different development in mathematics".
In a word, the teaching design of this course makes full use of the characteristics of the new curriculum experimental teaching materials, and integrates the new teaching years into the regular teaching, so that students' quality in related aspects has also been developed correspondingly in the process of learning facts and exercising their abilities.