Examination for civil servants: basic problems of digital operation and law of solving problems 1. Candidates should first make it clear that the questioner's intention is not to let candidates spend a lot of time on calculations. Most problems are a process of judgment and verification, rather than a process of calculation and discussion by ordinary methods. So there are often simple ways to solve problems. 2. Carefully examine the questions, quickly and accurately understand the meaning of the questions, and pay full attention to some key information in the stem of the questions; Through practice, we can sum up the exact meaning of all kinds of information and react quickly without hesitation. 3. Try to find a shortcut to solve the problem. Most calculation problems have shortcuts, and blind calculation can lead to answers, but it is a waste of time. Direct calculation is not the intention of the questioner. We must find the best training method at ordinary times. During the examination, according to the time situation, individual questions can be calculated by the general method. But we must find the best way at ordinary times. 4, through training and careful summary, try to master some mathematical operation skills, methods and laws, familiar with the common basic knowledge of mathematics; 5. Summarize the methods of solving common problems through practice; 6. Learning to use exclusion to improve mathematical operations mainly includes the following types of questions: basic problem-solving methods: 1, mantissa exclusion method: first calculate mantissa, then compare mantissa with mantissa in the answer one by one, and get the answer by exclusion method; 2. Simple calculation: use various simple algorithms of addition, subtraction, multiplication and division to get the answer. Through the explanation of the following examples, it will help you to deepen your understanding of the above methods and learn to use these methods flexibly to solve problems. 1, addition: Example 1, 425+683+544+828a.2480b.2484c.2486d.2488 Problem solving idea: first add the mantissa of each number, and then compare the obtained value with the mantissa of the answer one by one to get the answer. Add mantissa to determine that the mantissa of the answer is 0, BCD does not match, and the answer A is excluded; Example 2:1995+1996+1997+1998+1999+2000a,1985b. 3. Numbers close to 100, 200, 1000, 2000, etc. In various questions, it can be decomposed into such numbers plus or minus a number, so that the answer can be calculated more quickly. Example 3,12.3+45.6+78.9+98.7+65.4+32.1a.333b.323c.333.3d.332.3 Analysis: First add the decimal parts of each number in the question to get the mantissa, and then add the single-digit parts. Add the decimal point to get 3.0 excluding C, and add the digits before the decimal point of D to get 2+5+8+8+5+2. The mantissa is 0, and adding 3 determines that the mantissa of the answer is 3. The answer is a. Thinking of solving problems: 1. First add up the decimal points to get the mantissa, then compare them with the answers one by one, eliminate the answers with incorrect mantissa, and narrow the selection range. You can answer some questions at this time. 2. Add the numerical value obtained by adding single digits to the numerical value obtained by adding decimal points, and then compare the final numerical value with the rest of the answers, and generally you can get the correct answer. 2. Subtraction: Example 1, 9513-465-635-13 = 95113-(465+635). 489756-263945.28 = a.220810.78b.225810.72c.225811.72 Analysis: After the decimal point is added, the head and tail are separated. 3. Multiplication: Method: 1. Divide the number by multiplication, and the product will get integers similar to 1, 10, 100, which is easy to calculate. 2. Calculate the mantissa and get the answer by exclusion. Example 1,1.31×12.5× 0.15×16 = a.39.3b.40.3c.26.2d.26.3. Direct psychological mantissa:125× 8 =1000×15 = 303×131= 393 Only one case 2 meets the requirements. 119× 120 =120×120 =14400-120 = ... 123456× 654321= a.8077985376b.807985377c.8079853377 Analysis: The mantissa is 6, and the answer is A. On the surface, this kind of problem is difficult and complicated to calculate, but we should take into account that the problem is difficult. Therefore, it is easier to get the answer by mantissa calculation and elimination. Example 4: 125×437×32×25=() A, 43700000B, 87400000C, 87455000D, 43755000 The answer is A, and this question does not need direct calculation. Direct decomposition:125× 437× 32× 25 =125× 32× 25× 437 =125× 8× 4× 25× 437 =1000×/kloc. 85.7-7.8+4.3-12.2 = 85.7+4.3-(7.8+12.2) = 90-20 = 70 4532 = 4532× (79 ÷158) Kloc-0//2):a,1108000b, 1/20C, etc. This question only needs to list the formula, and then meet in pairs to get the answer. Candidates should have a good grasp of this type of question, and it is best to do the math by themselves.