Mathematical knowledge comes from life and is applied to life. Mathematician Hua once said: the universe is big, the particles are tiny, the speed of rockets, the cleverness of chemical engineering, the change of the earth, the complexity of daily use, and mathematics is everywhere. This is a wonderful description of mathematics and life. Mathematics teaching must start with the familiar life scenes and interesting things for students, so that they can have more opportunities to learn and understand mathematics from the familiar things around them, realize that mathematics is around, feel the interest and function of mathematics and experience the charm of mathematics.
For example, when teaching the understanding of numbers within 10, we should provide more familiar materials for "1 object", such as a cake, a person, a table, a boat and so on. In the process of social practice, I feel the distance of 1 km and 10 km; Go to the savings office to deposit and withdraw money, look at the interest rate table and feel the estimation of 1%, 2% and 4% interest; Go to the supermarket to see, weigh and estimate the weight of various vegetables and meat; Distribute exercise books, feel the average score and so on. These activities are deeply loved by students, which can not only enlighten the sense of mathematics, but also cultivate students' behavior of "being close to mathematics" and make mathematics learning full of fun.
Second, the sense of number comes from hands-on practice.
Piaget, a famous psychologist, said: "Children's thinking begins with action. If we cut off the connection between action and thinking, thinking cannot develop. " Hands-on practice is a special cognitive activity. In this dynamic cognitive activity, it not only satisfies the psychological characteristics of primary school students, such as strong curiosity, hyperactivity and good performance, but also concentrates attention and stimulates motivation. Enable students to experience the joy of success in their own creation and achieve real understanding. Hands-on practice is the first line of students' learning process, and it is also a free world for students to actively develop. The mathematics classroom that pays attention to hands-on practice will become a paradise for students to explore and a cradle for innovation. The cultivation of number sense is inseparable from hands-on practice.
For example, when teaching "trapezoidal area calculation", first review the area formula of triangle and its derivation process. Then let the students use scissors and trapezoidal paper to operate in groups and discuss with each other. Several different methods have been obtained successively; There are two identical trapezoids spliced into a parallelogram; Cut a trapezoid into two triangles along the diagonal; Cutting the trapezoid into parallelograms and triangles; Another method is to cut the trapezoid into triangles and then patch it. Finally, let the students discuss and summarize the area formula of trapezoid. In this way, the cultivation of number sense is implemented in specific operation activities, but students have deepened their understanding of mathematical knowledge and established a good number sense. Students not only gain knowledge, but also give full play to their subjective consciousness and cultivate their innovative consciousness.
Third, the sense of number comes from observation and thinking.
Observation is a lasting perceptual activity with purpose, plan and positive thinking, and it is the gateway of thinking. Any mathematical problem contains certain mathematical conditions and relationships. In order to solve the problem, it is necessary to observe the problem thoroughly and carefully according to its specific characteristics, and then carefully analyze it, and examine its essence through superficial phenomena, so as to have a sensitive feeling, feeling and perception of the problem and make a quick and accurate response.
For example, when teaching the law of product change, let students do the math by mouth and show the topic: 16╳2=32.
16╳20=320
16╳200=3200
16╳2000=32000
Then guide the observation: carefully observe the above four formulas, what do you find? (One factor remains the same, another factor changes, and so does the product. ) Comparing the second formula with the first formula, how does the second factor change? Where is Ji? What other formulas can be compared to draw this conclusion? If you compare the third formula with the first formula, what can you find? How does the fourth formula compare with the first one? From top to bottom, what rules can be found? What if you look from the bottom up? Therefore, the change rule of products can be obtained smoothly. The above teaching guides students to observe from whole to part, from part to whole, from top to bottom, and from outside to inside, and transforms static and conclusive mathematics into dynamic and exploratory mathematics activities, so that students have sufficient opportunities to engage in mathematics activities and help them experience the significance and role of mathematics in the process of subsidizing exploration, thus optimizing their sense of numbers.
Fourth, the sense of number comes from scientific training.
Basic knowledge of mathematics always plays a fundamental and leading role in the process of functional development. Without knowledge, it is impossible to form a sense of numbers. On the contrary, the better the sense of numbers, the more solid the knowledge, and the easier it is to activate. Therefore, classroom teaching should not only strengthen the teaching of basic knowledge, but also expand and deepen the practical content. Because the necessary scientific practice is an important way for students to feel the number of trips.
For example, after teaching complex multi-application questions, the following set of questions are involved:
(1) When Party A and Party B make parts, Party A is twice as short as Party B by 3, while Party A makes 15. How much does Party B do?
(2) Party A and Party B make parts, Party A is twice as much as Party B, and Party A makes 15 parts. How many parts does Party B manufacture?
(3) Party A and Party B make parts. Party A has three parts more than twice as many as Party B, while Party B makes 30 parts. How much does Party A do?
(4) Party A and Party B make two copies, Party A has three more copies than Party B, and two people make 54 copies. How much do Party A and Party B do respectively?
(5) Party A and Party B make two copies, with Party A making three fewer copies than Party B and two people making 48 copies. How much do Party A and Party B do respectively?
(6) A is smaller than B by 2 times 3, B is smaller than A 13, how much do A and B do respectively?
This group of questions looks very similar, but the method of solving problems has changed. We must think carefully and examine the questions, which is conducive to cultivating students' good sense of numbers. Often put the same, similar and different mathematical contents together, let students compare, observe and think carefully, understand the connections and differences among them, and deepen their ability to distinguish easily confused knowledge in comparison.
As the saying goes, "Rome wasn't built in a day", and the sense of numbers was never formed overnight. As a teacher, we should seriously absorb the new curriculum concept, study the teaching materials, creatively use the materials provided by the teaching materials, and skillfully design the teaching links to cultivate students' sense of numbers in classroom teaching.