1, tailing method

That is, the mantissa of each number is removed and the whole ten or hundreds of lines are taken for calculation.

2, into the law

That is, the highest digit of each number plus 1 is calculated as an integer of ten.

3. Rounding method

That is, mantissa is less than or equal to 4, mantissa is equal to or greater than 5, and it is calculated by integer ten or integer hundred.

4. Ten methods add up

That is, the related figures add up to close to 10.

5, a part of the whole

That is, divide a large whole into several parts on average, and calculate an integer according to the number of parts.

6. Make actual estimation according to certain standards.

That is, using the knowledge of counting units and measuring units learned to estimate the phenomena in real life, there are three common forms of this estimation.

The first is to estimate by counting unit; Second, use measurement units to estimate. For example, after learning M and cm, use this concept of space to let students estimate the height of desks, the length of blackboards and the height of classrooms from the ground to the windowsill.

The third is to estimate with an object as a reference. For example, given that the height of the door is 2m, Xiao Gang and Xiao Li are standing at the door respectively, and their height is estimated according to the position where their heads reach the door.

7. Rounding method

This method is the most widely used in daily life, and it is also the most basic estimation method in mathematics learning, that is, the quantity is regarded as an integer of 10000 and then calculated.

Methods to improve computing power

1, so that students can master arithmetic and algorithms skillfully.

Students should cultivate well-founded and organized thinking activities when learning any mathematics content. The calculation principle is to explain the basis and rationality in the calculation process. The algorithm of calculation is to explain the rules and logical order in the calculation process. When students learn to calculate clearly, it is convenient to calculate flexibly and simply, and the diversity of calculation is the foundation and possibility.

2. Combine solving practical problems with computing teaching.

Through specific situational teaching, students' interest in learning can be stimulated and their enthusiasm for learning calculation can be mobilized. In the process of learning calculation, students not only learned mathematics knowledge, but also solved problems in life, thus experiencing the joy of success.

Through specific situational teaching, students can awaken their life experience, activate their thinking, and explore calculation methods independently, so that students can master knowledge happily and easily in a relaxed atmosphere.

3. Computer teaching should focus on cultivating students' good study habits.

Cultivate students' habit of carefully examining questions. When teaching four operations, students are required to look at and draw two pictures when examining questions. In order to cultivate students' habit of careful calculation, students are especially required to write neatly, in a standardized format and in a reasonable way, not to rush, to think calmly and to calculate patiently. Cultivate students' habit of patient examination.