Chen Xiaoshi's What a coincidence
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Mathematics is gymnastics to exercise the brain. Whether calculating or solving problems, we should try our best to use simple algorithms or solutions according to the specific situation, so as to cultivate students' agility and flexibility in thinking purposefully. Many people have the experience that it is a pleasure to get the most beautiful and ingenious solution. Cleverness and stupidity are not only differences in methods, but also differences in ways of thinking. Clever calculation belongs to the thinking of seeking difference. It often has the characteristics of uniqueness, novelty and simplicity. This book systematically summarizes the methods, theories and skills of clever calculation from the aspects of the concept of number, calculation of number, application problems and preliminary knowledge of geometry. In the process of writing this book, I noticed the following points.
"Ok" Author: Li Tiaoqin Guo
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Calculation is the main content of primary school mathematics. Correct calculation is the basic requirement for learning mathematics well. You may not know, because the four operations in primary school are not enough, it will not only affect the current academic performance, but also affect the future study, work and life. Some people may not believe it. It is precisely because the addition and subtraction within 20 are unskilled that some candidates lose their focus and thus lose the opportunity to enter the university. From this perspective, it is not a simple question to be right. A large number of materials show that with the growth of grade, the correct rate of mathematical calculation is gradually decreasing. Why is this? Tracing back to the source, the key is that the foundation of primary schools has not been laid firmly. This problem is very serious.
The Key to Solving Geometric Problems: Unknown
How was geometry introduced?
Geometry is a subject that studies the properties of graphics. To study the properties of graphics, we can't only rely on observation, but also rely on measurement first. So why? Through judgment and reasoning. To do this, we must first learn the concept well, so as to understand the specific content of the topic; Secondly, we should learn axioms and theorems well, which are the basis of judgment and reasoning. These are all preparations for learning geometry well, and they are also the beginning of geometry introduction.