How to cultivate junior students' sense of numbers. 1 1, combined with specific realistic materials, perceive numbers within 100.
Students' rich activities are arranged in teaching materials, which embodies the idea that mathematics curriculum reform allows students to participate in the process of knowledge formation. In the theme map of the textbook, students use the number 100 to count different objects. Students choose different objects to practice counting in their lives. In the teaching process of this lesson, the teacher asked the students to count the number of things in front of them, and the process of showing the number made the students feel how much 10, how much is 20, and the ratio of 100 to 10 and more than 20. On the basis of students' perception of the numbers 10, 20 and 100, the teacher randomly takes something for the students to guess. What could it be? Suddenly, the enthusiasm of the students was mobilized at once, and they all told the results of their guesses. At this time, the teacher can count with the students and verify the results. The arrangement of this link in this lesson is divorced from books, and through vivid examples, I have a certain understanding of the number of logarithms. The new curriculum standard has spent a lot of time on the compilation of the textbook "Learning and Applying Mathematics", and many illustrations have infiltrated the idea of learning mathematics in life. The illustrations in the textbook inspired me a lot. Through these practical and multi-level operations and communication activities, students' awareness of independent participation has been exercised.
2. Comparative logarithm is an important aspect of cultivating students' sense of number.
The second volume of mathematics in the first day of the People's Education Press provides rich materials for cultivating students' sense of numbers.
2. 1 Compare numbers through specific feelings and cultivate a sense of numbers. The textbook encourages students to compare the size of 28 and 26 through the situation of "two chickens" in Example 8. Teachers can write interesting stories according to the theme map. Who has more eggs, the proud little yellow chicken or the proud little red chicken? This problem can be handed over to students in classroom teaching, so that students can think and communicate by themselves. Through observation and comparison, the students found that 28 was more than 26. The teacher put on an incredible expression and asked the students, How do you know? The students can't wait to tell their answers at this time. Some said: two little red chickens are missing, and four little yellow chickens are missing! Some people say that the little red chicken has five rows of eggs, five in each row and three in the sixth row, while the little yellow chicken has only 1 egg in the sixth row, so there must be many little red chickens. Students can see that 28 is greater than 26 through intuitive graphic observation. At this time, the teacher can guide the students to compare the sizes of 28 and 26 without the theme map. Students can use the knowledge they have learned before to compare the sizes of numbers according to the "order and composition of numbers". In the teaching of this lesson, let students compare the size of two numbers in different ways and get to know the size of logarithm.
2.2 Through the theme map of "Happy Fish" full of life situations and the description of the quantitative relationship, guide students to gradually establish a sense of numbers. The textbook is introduced with life examples, which makes students feel that there is mathematics knowledge everywhere in life. In the theme map of the textbook, there are mathematical problems caused by two children enjoying the beautiful goldfish. There are three fish tanks in the theme picture, and there are three kinds of goldfish in the fish tanks. Some are so dense that the fish seem to be suffocating; The others are fish swimming freely. Students can tell which kinds of fish are more and which kinds of fish are less at a glance. And it's easy to compare who has more fish and who has less fish. By comparing the number of fish with the students, the teacher deduces the number, thus describing the size of two numbers, and perceiving the number in the process of describing the number of things. This lesson is introduced through the dialogue between two little girls when designing exercises. Fangfang: My mother is 30 years old. Ping: My mother is older than yours! At the same time, there are 28, 32 and 38 answers for students to analyze and solve problems by themselves.
2.3 Develop students' sense of number through guessing games. In the textbook activity, an activity with strong life atmosphere and students' willingness to participate was arranged. Several children form a pile and guess how many little stars are in a * *. In the activity of "counting", I also prepared a handful of stars for students to estimate how many there are before class. The students were very interested and raised their hands and said a lot of numbers. I just waved my hand to show that I was wrong and said that I could help the child guess. The students quickly guessed how many stars there were according to the teacher's prompt! Then, give the initiative of the game to the students, let them play by themselves, write numbers, let others guess and give them appropriate hints. This kind of game not only mobilizes students' active participation, but also makes students feel the relationship between numbers and numbers in the game.
2.4 Comprehensive operation and perceptual characteristics. There are hundreds of pictures in the textbook. By asking students to supplement and observe, guide students to perceive the characteristics of numbers. In the teaching of this lesson, on the basis of students' completion of hundreds of digits, I ask students to find a three-digit number and a three-digit number respectively, and at the same time observe the relationship between the upper, lower, left and right digits in the hundreds of digits. At the same time, there are many forms, such as cross, suggesting that there is only one number in it, so that students can write other numbers.
3 Every bit of mathematics learning can cultivate students' sense of number.
Algorithm diversification is a new concept of mathematics learning, and the choice of operation method is closely related to students' sense of number. For example, in the teaching of "ten MINUS nine", after I derived the formula 12-9 from the situation, I was not in a hurry to teach students how to work out the number of this formula, but let them try to get the result of this formula by themselves. Some students swing with sticks, some students move beads on the counter, and some students try to calculate according to the vertical law they have learned before. Although students' hands-on and pen-writing operations are not necessarily standardized, they have experienced the process of knowledge formation, so they can understand the algorithmic significance of carry addition more deeply and establish a good sense of numbers.
4. Strengthen the cultivation of number sense in digital operation.
In operation, students' judgment of operation methods and estimation of operation results are closely related to students' sense of numbers. In the teaching process, we should attach importance to verbal calculation, strengthen estimation and advocate diversification of algorithms. In learning, students can experience the process of establishing mathematical model, estimating, solving and verifying the correctness and rationality of the solution from practical problems, and can understand the concepts of approximate number and effective number with the approximate range of rational number.
In practical teaching, choosing the appropriate algorithm in combination with specific problems will enhance the understanding of the practical significance of operation and cultivate students' sense of numbers. Learning operation is to solve problems, not just to calculate. In the past, mathematics teaching overemphasized the training of students' arithmetic skills and simply repeated meaningless topics. Students are not only bored, but also don't understand why they need to calculate, why they need to calculate in a fixed way, a question can be answered in different ways, and a formula can also determine the result in different ways.
With the growth of students' age and rich knowledge and experience, guiding students to explore the relationship and law between numbers and practical problems and mastering some tools to effectively express and exchange the relationship and changing law of numbers will further enhance students' sense of numbers, and combine the establishment of sense of numbers with the establishment of preliminary mathematical models, which will help improve students' overall mathematical literacy.
How to cultivate students' sense of numbers in grade two. First, improve their consciousness by learning standards.
"Mathematics Curriculum Standard for Full-time Compulsory Education (Experimental Draft)" puts forward "number sense" for the first time, which has achieved a leap from ignoring the cultivation of number sense in the past to attaching importance to it. We can find the concrete description of number sense in the description of learning content, and further summarize the main manifestations of number sense. For example: understand the meaning of numbers and express them in various ways; Grasp the relative size of numbers in specific situations, and express and exchange information with numbers; Select the appropriate algorithm, estimate the operation result of solving the problem, and so on. What deserves special attention is that some researchers have investigated and interviewed primary school teachers on the content of number sense, and found that under the background of new curriculum reform, more than 90% teachers know the core concept of number sense, but they can't tell the connotation of number sense, let alone the components of number sense. More importantly, although more than 80% teachers think that the sense of number is very important to promote the development of primary school students' mathematics, they don't know much about the ways to cultivate the sense of number. Therefore, we should further rationally interpret the curriculum standards, timely understand the misunderstanding of cultivating number sense in primary school mathematics classroom teaching, correct the phenomena of ignoring students' personal experience and emphasizing conclusions over processes, and constantly improve the consciousness of cultivating number sense.
Second, combined with the creation of situations to mobilize enthusiasm
Life is the source of innovation. In teaching, we should be good at creating situations full of life breath, let students stay in them, stimulate students' potential desire for innovation, and make students like mathematics. For example, when teaching the nature of subtraction, we can create such a situation: Xiaogang takes 100 yuan and wants to buy a gift for his two good friends. Xiaogang took a fancy to four things: schoolbag 16 yuan, pencil case 14 yuan, football 44 yuan and racket 36 yuan. Students guess which two gifts Xiaogang will buy? If there is still money, how much is left? How to calculate in the form of columns? What are the characteristics of the listed formulas? This reproduces the scene of students paying for shopping at ordinary times, so that students can understand both the truth and the law. At the same time, in teaching, teachers should pay attention to the factors related to real life, so that students can experience the meaning and value of what they have learned from the living situation and stimulate their learning consciousness and enthusiasm.
Third, combine mathematical activities to stimulate inquiry.
Practice shows that students are most likely to accept and understand their own conclusions. In mathematics activities, students do mathematics by themselves, which is beneficial to truly understand and perceive mathematical knowledge, form a sense of numbers on this basis, and further improve their mathematical application ability. For example, when teaching the understanding of meters and centimeters, we can design the following operation activities from the reality of junior students: first, measure by hand, and let students draw the length of 1 meter with their own arms and 1 cm with the width of their index fingers. When using these weighing scale, experience the lengths of 1 m and 1 cm. The second is to motivate students to find out which objects in life are about 1 m and 1 cm in length. Third, let's take a walk. Let the students walk naturally from the back of the classroom to the front, count the steps to make clear the actual length of the classroom. For another example, when teaching grams and kilograms, the following teaching activities can be designed: first, let students weigh a bag of salt, a bar of soap and a basket of apples. Second, weigh it. Let the students weigh with their hands and feel the weight of 1 kg apple with their eyes. The third is counting. Let the students count. How many apples are there in a catty? Let the students "touch" mathematics in the activities, so as to correctly establish the measurement concepts such as l gram, 1 kg, l meter and 1 cm in their minds. Then, use these direct experiences to measure the weight or length of related items in life, effectively avoiding the mistake that a bed is 2 cm long and a cow weighs 200 grams. In fact, game activities and practical activities are both forms of learning that students like very much. For example, in a guessing game, you can guess the price of a refrigerator. In this guessing game, students can compare numbers according to the specific situation, and they can also feel the mathematical idea of approaching with "interval set", which is very beneficial to cultivate the sense of numbers.