Recently, the child just learned to write and borrow subtraction, and before he was very skilled, he began to solve the mixed operation of addition and subtraction with oral calculation, either miscalculating or forgetting to borrow. Oral arithmetic is prone to mistakes. I suggested that he do it with a pen. He gave me a white look and said, the teacher won't let me do it with a pen, so why use it? I have said all the reasons I can think of, but it will not change. I can't do anything unless the teacher says so. ...
First of all, find the mystery between the numbers in the formula and simplify the complex numbers.
In fact, I also thought that since he is willing to do oral calculations, we can practice (although this is not my strong point). I happened to see the video of quick math calculation in primary school, and I thought the method was quite good. Later, after watching many similar videos, I felt that there were many routines here, but I couldn't find their unique cheats at all. I gradually began to worry about how many algorithms to remember to quickly retrieve the simplest one. This method obviously doesn't work for me. Memory is limited!
Just when my initial enthusiasm for quick calculation began to fade, I saw the book 10 times mental arithmetic. Seeing that the catalogue is basically full of answers to various calculation problems, I have to have a quick look and see if there are any clever tricks to mentally calculate these calculation problems that obviously need to be written. Let me see: 678+456=? Usually, the vertical type of three-digit operating column is the most reliable. Now I will apply the exchange method and combination method mentioned in the book.
678+456=600+70+8+400+50+6=600+400+70+50+8+6= 1 134
It's really better to break it down into integers. In fact, the column is not just a point that children forget to carry.
Oral addition is relatively easy. Let's try double-digit multiplication again. I think it is really difficult to get rid of vertical multiplication. 74× 12=? Let's take a look at the slow-motion playback of mental arithmetic in the book:
74× 12=74×( 10+2)=74× 10+74×2=888
The operation process is shown in this way, and children can understand it. Multiplying by whole ten is really simple.
I've tried the decimal problem. Children have never learned it, so I experienced it alone, because the decimal problem is easy to make mistakes, especially when the number of digits after the decimal point is different, and the column is vertical. ?
3.5- 1.5 1=? First, subtract 1.5 from the previous two terms to get 2-0.0 1= 1.99. In the book, the numbers in the formula are simplified to an integer and a decimal by intensity subtraction. After understanding this problem, it is not difficult to understand the next one.
Decimal conversion: 49÷87.5=? 49÷87.5=0.49÷0.875=0.49÷7/8=0.49×8/7=0.56
Second, the mathematical formula, can learn is limited, we should expand the part that we can't learn.
The book 10 Double Speed Mental Arithmetic is a collection of different mental arithmetic methods. Mental arithmetic is actually looking for the law between numbers. Faced with different formulas, I can find the simplest method among many problem-solving schemes. This is my initial cognition. In fact, I really need to remember the method and then apply it. However, there are many methods in the book 10 times speed mental arithmetic, which actually feels more than application. More often, I can remind myself how to calculate simply through digital association and operation symbols. Of course, familiarity with methods is the foundation, so that ideas can be opened. This is the part of knowledge that can't be learned in this book column. It is a method that is independently explored and summarized after mastering various calculation methods. It really takes some skill to reach this level.
The book 10 times speed mental arithmetic contains 56 mental arithmetic skills in primary and secondary schools. I only learned the calculation methods commonly used in primary schools, which is relatively simple. But I can still feel that the methods mentioned in the book still inspire me to find the laws and relationships between numbers. Of course, this book has not attracted enough attention from children because he has not been able to independently understand the convenience of calculation methods from the steps described in words. But learned the method of additive commutative law and associative law from the slow motion playback of exercises.
This book is very suitable for parents to guide their children to learn mental arithmetic methods, examples and various solutions. Whether it is through text explanation or slow-motion playback of practice, it is a display of ideas. Parents can guide and expand their children's problem-solving thinking, and can also help them gradually get rid of what the teacher has said or taught before they can accept new methods and enter the state of active learning.
Third, analyze the problem step by step according to the steps of understanding, hypothesis and practice.
To help children enter this active learning state, you can read the book Magic Logic Thinking Game Book, which is published in the same set as 10 times speed mental arithmetic. This book is more intuitive and interesting, highlighting the elements of the game and making it exciting to solve every math problem. I noticed that the title of this book came from "Interesting Mathematics in the World", aiming at cultivating children's ability to see problems from multiple angles, which surprised me deeply. Faced with the problems in this book, the child quickly began to invest. Once the answer is correct, he cheers and can also tell his own ideas for solving the problem. This is an exercise calculation. If you get a hundred points, you can't see it.
The titles in the book "Magic Logic thinking the game" are displayed in the form of color pictures, which is more intuitive. The analysis is also graphical, especially the arrangement order. For example, the problem of the cinema is based on tips. It is not difficult to find someone's seating order. My children and I did the right thing. However, seeing the analysis provides two verification ideas, which are different from ours. The steps of analysis expand our thinking. It turns out that this kind of problem can list all the hypothetical situations, and then compare the conditions to see who meets the results. This method is great.
I have to say that graphic analysis is more direct, listing all the hypothetical situations and calculating the results. Finally, the nonconformities are eliminated, and the correct results are obtained. In this process, the child's ability to read pictures begins. This analysis process is very enlightening for children. He can realize that his unexpected assumptions are actually necessary for analyzing problems. Drawing is also a common method to solve mathematical problems. Children can clearly feel it and it is very helpful to clarify their thinking.
Usually, when you encounter math problems that you can't solve, you are easily impatient and even have the idea of giving up. Now I have to remind myself to assume and have a look. Through this idea, I solved the additional problem of yesterday's children's homework. I couldn't deduce the steps to solve the problem yesterday, which was simply depressing. Today, it is really amazing to work out the correct answer directly according to the steps of cognition, hypothesis and practice.
There is also the problem of origami. Five pieces of paper of the same size do not completely overlap. Guess which one is the bottom. We answered this question wrong, because our thinking was wrong. The analysis is divided into three steps to verify whether the largest one is at the top, remove the top or the largest one is at the top, and so on, and quickly find the fifth one. This method is more intuitive.
Although we use the method of exclusion, it is almost the result of speculation, which is the limitation of thinking. The Book of Magical Logic thinking the game goes deep into the core of the problem layer by layer through illustrations and assumptions until the problem is solved. Learning this step is like a spring breeze, and I feel that math problems can be answered calmly. Follow the steps of cognition, hypothesis and practice, or draw pictures, or apply formulas to calculate. Each step of the chart has its strict logic, through which reasoning can be carried out.
My children and I named this book "The Book of Magical Logic of Thinking Games". After I answer the questions correctly, the children always proudly say, "Look, I'm smart, let me tell you this question …" The children are very active and confident. Isn't that what I expect him to be? Now it is increasingly found that I want to study with my children, and he can adjust his attitude from my learning attitude. And he is willing to show himself, so he can't help with his math homework in the future.
Yao's "embarrassment" and "horizontal", if you know it, you will know it, and if you don't know it, you will go to school. This set of books can be accompanied to middle school.
Recalling the logic mathematics that children learned in kindergarten, I am still surprised that such a young child should learn logic. But the explanation after the child's experience is straightforward. The simplest mathematics is to find the law. As long as we find the rules, we can solve many problems. At that time, I especially admired him for saying such feelings. When I came into contact with computing, I began to drill into the dead end of computing more than once, even me. It's really tiring to invest like this. I didn't begin to reflect until I collapsed, and then I began to pull myself back to the normal mathematical thinking track by reading books on mathematics. However, once you encounter new problems, you may deviate from the track of mathematical thinking and walk into a dead end ... So you should not only practice and calculate more, but also read more books to deeply understand the characteristics of thinking and exercise your thinking ability, especially books on mathematical thinking.