How to cultivate children's verbal ability? The verbal calculation is also satisfactory. It is a calculation method that directly calculates numbers without using calculation tools, mainly relying on thinking and memory. The new syllabus points out that oral calculation is not only the basis of written calculation, estimation and simplification, but also an important part of calculation ability. It can be seen that to cultivate students' computing ability, we must first start with oral computing ability. So how to cultivate students' oral ability? My experience is that it is very important for teachers to read the three-character classics well: "foundation (grasping the foundation), teaching method (teaching method) and practicing method (routine training)" Reading the word "base" well means basic oral calculation. Oral calculation in primary school mathematics teaching can be divided into three categories: basic oral calculation, general oral calculation and special oral calculation. These three kinds of oral calculation are mainly based on the content of basic oral calculation, which is the basis of calculation. Basic oral calculation must require proficiency, and proficiency refers to "blurting out", while the other two types of oral calculation only require proficiency or learning. Therefore, we should pay attention to the following aspects:

1. Visual representation of oral calculation

From the form of operation, the oral calculation in the lower grades of primary school is a transition from intuitive perception to imagery operation. For example, we should establish the appearance of "9+2" in teaching: first show a box with 9 balls, and then prepare 2 balls for students to think. "How can I see how many balls are in a * * * at a glance?" Soon a student said, "I took 1 ball out of the two balls outside the box and put it in the box." There are 10 balls in the box, and there is one outside, a * * *1/." I praised this classmate for speaking well, and explained that this method is called "adding ten", that is, when I see 9, I think of 9, and how much it constitutes 10. In this way, the appearance is established, and the accuracy of oral calculation has a foundation.

2. Manage liquidation and help oral calculation.

The teaching of oral calculation is not to pursue the speed of oral calculation, but to let students understand the truth. Only by understanding the reasons can we effectively master the basic methods of oral calculation. Therefore, we should attach importance to the teaching of mathematical theory. For example, when teaching 8+5 = 13, we should start with the actual operation and let students understand that 8 is less than 10. Add 8 and 5, divide 8+5 by 2 and 38+58 and 2 to form 1023 10 and add 3 to get 65438. 10 and draw a thought process diagram of 8+5 = 13. On the basis of students' full understanding of arithmetic, simplify the thinking process and abstract the rules of carry addition: "Look at a large number, divide it into decimals, make it 10, and add a few more." Finally, guide students to think about how to calculate "5+8". In this way, students understand arithmetic and master the basic methods of oral calculation.

3. Reasoning training is helpful for oral calculation.

Doing a good job in reasoning training can enable students to effectively master basic oral calculations and cultivate the flexibility of thinking. For example, if you teach abdication subtraction within 20 minutes, you should display "13-8 =?" At the beginning of class. Ask the students: "What is 13-8?" "equal to 5." Ask again: "How did you come up with it?" "Do subtraction and want to do addition." Encourage students again: "Can you think of another method of oral calculation?" After students say several oral arithmetic methods, they sum up different abdication subtraction methods, and ask students to strengthen reasoning training of different methods to improve the speed of oral arithmetic. Memorizing the word "teaching" well means teaching students the methods and rules of oral calculation.

When students are proficient in basic oral arithmetic, they should be transferred to plateau training, that is, teaching students the methods and rules of oral arithmetic:

(A) with "add up to ten" oral calculation

According to the characteristics of the formula, apply laws and properties to "round" the operation data:

1. Appendix "Overview"

For example, 14+5+6 =? Enlighten students: Add up several figures. If several numbers add up to an integer 10, you can change the position of the addend and add up several numbers.

2. Use the nature of subtraction to "round off"

For example, 50- 13-7, to inspire students to tell their thinking process, tell several oral calculation methods and compare them, so that students can draw a conclusion: if you subtract several numbers from a number continuously, if the sum of subtraction can add up to an integer, you can add the subtraction first and then subtract. This kind of oral calculation is relatively simple.

3. Multiplication factor "rounding"

Such as 25× 1? The product of 4× 4, 25 and 4 is 100, and the result can be calculated directly by mouth.

(B) the use of "decomposition" oral calculation

It is to "disassemble" a number in the topic and calculate it with another number, such as 2? 5×32, the original formula becomes 2? 5×4×8= 10×8=80。

(C) using some quick calculation skills for oral calculation

1. Two digits are quickly multiplied by the first and last digits 10.

That is, multiply the number on one of the ten digits by 1, and the product is one hundredth and one thousandth of the product of two numbers, and then the product of the numbers on two numbers is one and one tenth of the product of two numbers. For example, 14× 16 = 224 (4× 6 = 24 is a unit, 10 digits, (1+ 1) × 1 = 2 is a hundred digits).

2. Fast multiplication of two digits of head difference 1 and tail difference 10. That is to say, the square of the ten digits of the larger factor MINUS the square of its single digits. Such as: 48× 52 = 2500-4 = 2496.

3. Use the "benchmark number" for quick calculation.

For example, 623+595+602+600+588 can choose 600 as the base number, first accumulate the difference between each number and the reference number, and then add the product of the base number and the number of items.

(d) Memorizing commonly used data

Such as: 65438+ the square of 0 ~ 20 of each natural number; To read the word "practice" well means to practice oral arithmetic often. The formation of speech ability can only be achieved through routine training, and the training should be diversified.