［作业］设负载阻抗为Z l =100+j50Ω接入特性阻抗为Z 0=50Ω的传输线上。f =1000MHz
1）用单支节调配法实现负载与传输线匹配，通过Smith 圆图求解。 2）用LC 匹配网络实现负载与传输线匹配，通过Smith 圆图求解。 解： 1）
解一：（开路支节）
负载阻抗归一化0
21L Z Z Z j ==+Ω ，在阻抗圆图上找到负载对应的A 点，在驻波比圆上转动直到与圆1+jb 相交，得到B 点（绿色线路径1）和B ’点（红色线路径1），可读出负载的归一化导纳分别为11L
Y j S =+ ，11L
Y j S =- ，由径向线在相位标尺上的角度可知，A 点到B 点旋转的角度为θ=144o ，A 点到B ’点旋转的角度为θ1=270o ,因此支节到负载的电长度分别为θ/2=72o 和θ1/2=135o ，即支节的接入位置分别为d=0.2λ ，d 1=0.375λ.
为了抵消B 点和B ’点中的电纳，截短线的归一化电纳为1j S 。由开路点D 点，沿ρ=∞圆顺时针转到1j S 的E 点（绿色线路径2）和E ’（红色线路径2）点。由相位标尺上的角度可知,D 点到E 点旋转的角度为θ=270o , D 点到E ’点旋转的角度为θ1=90o ,所以支节的长度为分别为θ/2=135o 和θ1/2=45o ，其对应的电长度分别为0.375λ、0.125λ，
因此支节线长度: E 点接入l =0.375λ。 E ’点接入l 1=0.125λ。
解二：（短路支节）
负载阻抗归一化0
21L Z Z Z j ==+Ω ，在阻抗圆图上找到负载对应的A 点，在驻波比圆上转动直到与圆1+jb 相交，得到B 点（绿色线路径1）和B ’点（红色线路径1），可读出负载的归一化导纳分别为11L
Y j S =+ ，11L
Y j S =- ，由径向线在相位标尺上的角度可知，A 点到B 点旋转的角度为θ=144o ，A 点到B ’
点旋转的角度为θ1=270o ,因此支节到负载的
电长度分别为θ/2=72o和θ1/2=135o，即支节的接入位置分别为d=0.2λ，d1=0.375λ.
为了抵消B点和B’点中的电纳，截短线的归一化电纳为1j S
。由短路点F点，沿ρ=∞圆顺时针转到1j S
的E点（绿色线路径2）和E’（红色线路径2）点。由相位标尺上的角度可知,F点到E点旋转的角度为θ=90o, F点到E’点旋转的角度为θ1=270o,所以支节的长度为分别为θ/2=45o和θ1/2=135o，其对应的电长度分别为0.125λ、0.375λ，因此支节线长度:
E点接入l=0.125λ。
E’点接入l1=0.375λ。
2）
解一：
负载导纳归一化00.40.2L
Y Z Z j S ==- ，在导纳圆图上找到负载对应的A 点，从负载朝源端看，并联一个电容，A 点从导纳圆上沿路径1旋转直到与1+jx 的阻抗圆相交，得到B 点，可读出B 点负载的归一化导纳为0.4+j0.49S ，,则ΔB=j0.69S ，由 0B cZ ω?=，得C=2.2pF ；然后串联一个电感，改变电抗，B 点在阻抗圆上沿路径2旋转直到1+j0Ω，B 点的归一化阻抗为1-j1.224Ω，所以电抗的该变量为ΔX=-j1.224Ω，由0
L X Z ω?=，得L=9.74nH
B
A 0.4-j 0.2S
0.4+j 0.49S/
1-j 1.224Ω
1
2
解二：
解：负载导纳归一化00.40.2L Y Z Z j S ==- ，在导纳圆图上找到负载对应的A 点，从负载朝源端看，并联一个电感，A 点从导纳圆上沿路径1旋转直到与1+jx 的阻抗圆相交，得到B 点，可读出B 点负载的归一化导纳为0.4-j0.49S ，,则ΔB=-j0.29S ，由 0Z B L
ω?=，得L=27.5nH ；
然后串联一个电容，改变电抗，B 点在阻抗圆上沿路径2旋转直到1+j0Ω，B 点的归一化阻抗为1+j1.224，所以电抗的该变量为ΔX=j1.224S ，由0
1X CZ ω?=
，得C=2.6pF
0.4-j 0.2S
0.4-j 0.49S/1+j1.224Ω
A B
1
2
C语言常见复习题及参考答案 一、选择题 1.下述标识符中，（）是合法的用户标识符。 A.A#C B.getch C.void D.ab* 2.在C语言中，字符型数据在内存中是以（）形式存放的。 A.原码 B.BCD码 C.反码 D.ASCII码 3.以下选项中不合法的用户标识符是（）。 A.abc.c B.file C.Main D.PRONTF 4.以下选项中不合法的用户标识符是（）。 A.123 B.printf C.Anbsp; D.Dim 5.可以在C语言程序中用做用户标识符的一组标识符是（）。 A.void B.as-b3 C.for D.2c define -123 -abc Do WORD If cas SIG 6.在以下各组标识符中，合法的用户标识符是（1）、（2）、（3）。 （1）A.001 B.table_1 C.0_t D.k% Int t*.1 W10 point （2）A.Fast_ B.void C.pbl D. Fast+Big abs fabs beep （3）A.xy_ B.longdouble C.*p D.CHAR 变量1 signed history Float 7.（）是构成C语言的基本单位。 A.函数 B.过程 C.子程序 D.子例程 8.若有说明：char s1='\067';char s2="1";char s3='1';则s1中(1),s2中(2),s3中(3)。
（1）.A.包含3个字符 B.包含2个字符 C.包含1个字符 D.无定值，说明不合法 （2）.A.包含1个字符 B.包含2个字符 C.包含3个字符 D.无定值，说明不合法 （3）.A.包含1个字符 B.包含2个字符 C.包含3个字符 D.无定值，说明不合法 9.若x为int型变量，则执行以下语句后,x的值为 x=6; x+=x-=x*x A.36 B.-60 C.60 D.-24 10.在C语言中，char 型数据在内存中是以（）形式存储的。 A.原码 B.补码 C.ASCII码 D.反码 11.以下运算符中优先级最低的算符为（），优先级最高的为（）。 A.&& B.& C.|= D.|| E.?: F.!= 12.若有运算符>、*=、<<、%、sizeof，则它们按优先级（由低至高）的正确排列顺序为 A.*= << > % sizeof B.<< *= > % sizeof C.*= > << sizeof % D.*= > << % sizeof 13.若有以下类型说明语句 char w; int x; float y; double z; 则表达式w*x+z-y 的结果是（）类型。 A.float B.char C.int D.double 14.若w,x,y,z 均为int 型变量，则执行下面的语句后, w=(1), x=(2), y=(3), z=(4)。 w=5; x=4; y=w++*w++*w++; z=--x*=--x*--x;
配对求和 引入：被人誉为“数学王子”的高斯在年仅10岁时就以一种非常巧妙的方法很快求出1+2+3+4+5+、、、+99+100的结果。高斯是怎样求出这个和的呢？这就是我们要研究的这种求和的方法。 我们利用高斯的巧算方法得出这样的公式： 总和=（首项+末项）×项数÷2 项数=（末项-首项）÷公差+1 末项=首项+（项数-1）×公差 第一类题型 例题1： 计算：1+2+3+4+5+、、、+98+99+100. 思路点拨： 此数列是一个等差数列，公差是1，我们可以利用“总和=（首项+末项）×项数÷2”的求和公式来解。 解：1+2+3+4+5+、、、+98+99+100 =（1+100）+（2+99）+（3+98）+、、、+（50+51） =（100+1）×（100÷2） = 101×50 = 5050 同步精炼： 1、1+2+3+4+5+6+7+8+9+10 2、2+4+6+8+、、、+30 第二类题型 例题1： 计算：2+5+8+11+14+17+20 思路导航： 本题是一个等差数列，公差是3. 2、5、8、11、14、17、20，一共有7个数，如果我们仍像例1那样每两个数组成一个组，就多出一个数，那怎么办呢？我们不妨这样想： 2 5 8 11 14 17 20 +20 17 14 11 8 5 2 22 22 22 22 22 22 22 7个22是154，而154是两组2到20的和，一组2到20的和一组2到20的和就是154÷2=77，由此我们得出这样的规律，当加数是单数时，就可用第一个数即前项与最后一个数（末项）相加，乘以这组数的个数（项数），再除以2，就能求出正确结果了。其实这种方法也适用于加数的个数成双的求和：
英语四级长篇阅读段落信息匹配题练习及答案解析（2） Section B Directions：In this section，you are going to read a passage with ten statements attached to it.Each smtement contains information given in one of the paragraphs.1ndentify the paragraph from which the information is derived.You may choose a paragraph more than once.Each paragraph is marked with a letter.Answer the questions by marking the corresponding letter on Answer Sheet 2. Creative Book Report Ideas A.Are you at a loss for creative book report ideas for your students?If yes.then this article will help you make reading and reviewing books more creative for your class.In an age of PSPs，Xbox，anime and gaming arcades，reading has lost its foothold in the list of hobbies that children tend to cite. Most of the reading that kids do today,comes in the form of compulsory books that they need to read for school and maybe that is the reason they find reading to be an insurmountable and boring task.If you want to inculcate the love for languages and literary masterpieces in your students and want them to devour books everyone should read，then a good way of going about the same would be to get them to start working on creative book report ideas.While working on creative ideas for book reports，your students will have to understand the book in a way that allows them to come up with new ways to present to the class，the essence of the book. B.As a teachel while egging your students to activate their creative gray cells.you will have to help them out with basic ideas that they can work on.Depending on the age bracket that your students belong to，the creative book report ideas will vary.This is so，not just because of the varying attention spans that children of various age groups posses but also because of the amount of work that kids can put into the report.While a middle school student wiIl be comfortable handling a handy cam，a student from elementary school will be more fascinated if he is working with paints and puppets.So do you want to know how to write a book report creatively?In this article.we will list out for you，a couple of good creative book report ideas for elementary students and for middle school students. C.A book report sandwich is a good creative idea for book reports.As a teacher you can get drawings of a sandwich on sheets of Paper that are of the color of the ingredients of your sandwich，for example，a cream sheet of paper to resemble mayonnaise，red to represent tomato and likewise.Ob. viously,each ingredient should be cut in a way that when assembled together,it looks like a sandwich.Now,give each of your students one of these book sandwiches to create their book report. It can start with the name of the book and the author’s name on the top slice of the sandwich.The second ingredient can have the summary of the book on it.Each subsequent ingredient can have a description of the main characters，the setting of the book，the plot，and then his or her views about the book.Once they are done with their book reports，they can staple the book sandwich together and then，you can create a class bulletin board with all the book report sandwiches on display. D.One of the good techniques to retell a story,it is also one of the favorite creative book report ideas among students.The job that the student will have is to read the book and then pick a few objects at his/her home which will allow him/her to retell the story in a way that makes it interesting for his/ her audience.Every time he/she picks out an object from the bag to report the book he/she has read，there has to be a valid connection between the book and the object，which the student can first ask the audience to guess and then go ahead and explain it.This idea is spin —off on the normal show and tells and allows for an interactive book report session. E.This is one of the creative ideas for book reports in which.as the teacher, you will have to divideyour class into groups and give them one book each.The students can then read the book
C 语言理论上机考试选择题部分（共200题） 1、下面程序的输出是___D______ #include
a+=a-=a*a 后,a 的值是____D____ A) 552 B) 264 C) 144 D) -264 9、执行下面程序中的输出语句后,输出结果是____B__. #include
1在诸多社会环境中，对会计的产生和发展起决定作用的是（）。 A: 政治环境 B: 经济环境 C: 教育环境 D: 其他环境 2对会计的产生和发展具有决定意义的环境有（）。 A: 经济环境 B: 政治环境 C: 教育环境 D: 自然环境 E: 科技环境 3在下列各种职能中，被称为会计基本职能的有（）。 A: 核算职能 B: 预测职能 C: 监督职能 D: 决策职能 E: 分析职能 4在下列各项中，能够概括会计本质特征的有（）。 A: 具有核算和监督两种基本职能 B: 主要以价值形式进行管理 C: 具有连续性、系统性、全面性和综合性 D: 主要以实物形式进行管理 E: 具有自然和社会双重属性 5下列各项中，属于企业会计对象基本内容的有（）。 A: 资产 B: 负债 C: 所有者权益 D: 收入 E: 支出 6企业资金运动的特点主要有（）。 A: 循环与周转方式 B: 具有并存性 C: 具有继起性 D: 具有补偿性 E: 具有增值性 7在我国，关于会计目标的代表性观点有（）。 A: 管理活动论 B: 决策有用论 C: 受托责任论 D: 信息系统论 8根据我国《企业会计准则》的规定，财务会计报告应向会计信息的使用者提供的信息有（）。A: 与企业财务状况有关的会计信息 B: 与企业经营成果有关的会计信息 C: 企业管理层受托责任履行情况
D: 与企业现金流量有关的会计信息 E: 与企业经营管理有关的会计信息 9会计分期假设建立的基础是（）。 A: 持续经营假设 B: 会计主体假设 C: 货币计量假设 D: 会计期间假设 10会计假设也称会计的（）。 A: 基本职能 B: 基本前提 C: 基本理论 D: 基本方法 11在下列各项中，属于会计基本假设的内容有（）。 A: 会计主体 B: 持续经营 C: 会计对象 D: 会计分期 E: 货币计量 12下列说法中，关于会计主体假设的准确的说法有（）。A: 以一定经济组织发生的各项交易或事项为对象 B: 明确了会计所服务的对象 C: 明确了会计核算的空间范围 D: 便于分期结算账目和编制财务会计报告 E: 便于汇总和综合 13会计假设所做出的基本假定有会计的（）。 A: 核算范围 B: 核算内容 C: 基本程序 D: 基本方法 E: 基本职能 14进行会计分期的主要目的有（）。 A: 进行账户设置 B: 分期结算账目 C: 确定会计核算空间范围 D: 编制财务会计报告 E: 确定会计核算时间范围 15前国务院总理朱镕基为北京国家会计学院的题词是（）。A: 诚信为本，操守为重，遵守准则，不做假账 B: 诚信为本，遵守准则，操守为重，不做假账 C: 诚信为本，操守为重，遵守原则，不做假账 D: 诚信为本，信用为重，遵守准则，不做假账 16下列各项原则中，也可称为有用性原则的是（）。 A: 可比性原则 B: 相关性原则
大学英语四级信息匹配练习题一 Directions: In this section, you are going to read a passage with ten statements attached to it. Each statement contains information given in one of the paragraphs. Identify the paragraph from which the information is derived. You may choose a paragraph more than once. Each paragraph is marked with a letter. 长篇阅读 Preparing for Computer Disasters A) Summary: When home office computers go down, many small businesses grind to a halt. Fortunately, taking steps to recover from disasters and minimize their effects is quite straightforward. B) Fires, power surges, and floods, they're all facts of life. We read about them in the morning paper and see them on the evening news. We sympathize with the victims and commiserate over their bad luck. We also shake our heads at the digital consequences—melted computers, system failures, destroyed data. Yet, somehow, many of us continue to live by that old mantra of denial: "It won't happen to me." Well, the truth is, at some point you'll probably have to deal with at least one disaster. That's just how it goes, and in most aspects of our lives we do something about it. We buy insurance. We stow away provisions. We even make disaster plans and run drills. But for some reason, computer disaster recovery is a blind spot for many of us. It shouldn't be. Home computers contain some of our
英语四级段落信息匹配题强化训练 段落信息匹配题是四六级改革之后的新题型，很多同学还不是很熟悉，以下是小编为同学们整理的英语四级长篇阅读段落信息匹配题练习，希望对各位有所帮助。 Jaguars Don't Live Here Anymore A)Earlier this month, the United States Fish and Wildlife Service announced it would appoint" critical habitat" for the endangered jaguar. Jaguars--the world's third-largest wild cats, weighing up to 250 pounds, with distinctive black rosettes ( 玫瑰花色) on their fur--are a separate species from the smaller, tawny (黄褐色的) mountain lions, which still roam large areas of the American West in the United States and take the first steps toward mandating (批准) a jaguar recovery plan. This is a policy reversal and, on the surface, it may appear to be a victory for the conservation community and for jaguars, the largest wild cats in the Western Hemisphere. B) But as someone who has studied jaguars for nearly three decades, I can tell you it is nothing less than a slap in the face to good science. What's more, by changing the rules for animal preservation, it stands to weaken the Endangered Species Act. C)The debate on what to do about jaguars started in 1997, when, at the urging of many biologists ( including me), the Fish and Wildlife Service put the jaguar on the United States endangered species list, because there had been occasional sightings of the cats crossing north over the United States-Mexico border. At the same time, however, the agency ruled that it would not be "prudent" (谨慎的) to declare that the jaguar has critical .habitat--a geographic area containing features the species needs to survive--in the United States. Determining an endangered species' critical habitat is a first step toward developing a plan for helping that species recover. D)The 1997 decision not to determine critical habitat for the jaguar was the right one, because even though they cross the border from time to time, jaguars don't occupy any territory in our country--and that probably means the environment here is no longer ideal for them. E)In prehistoric times, these beautiful cats inhabited significant areas of the western United States, but in the past 100 years, there have been few, if any, resident breeding populations here. The last time a female jaguar with a cub ( 幼兽) was sighted in this country was in the early 1900s. F)Two well-intentioned conservation advocacy groups, the Center for Biological Diversity and Defenders of Wildlife, sued the Fish and Wildlife Service to change its ruling. Thus in 2006, the agency reassessed the situation and again determined that no areas in the United States met the definition of critical habitat for the jaguar. Despite occasional sightings, mostly within 40 miles of the Mexican border, there were still no data to indicate jaguars had taken up residence inside the United States. G ) After this second ruling was made, an Arizona rancher ( 牧场主), with support from the state Game and Fish Department, set infrared-camera (红外摄像机) traps togather more data, and essentially confirmed the Fish and Wildlife Service's findings. The cameras did capture transient jaguars, including one male jaguar, nick named Macho, B, who roamed the Arizona borderlands for more than a decade. But Macho B, now dead, might have been the sole resident American jaguar, and his extensive travels indicated he was not having an easy time surviving in this dry, rugged region. H) Despite the continued evidence, the two conservation advocacy groups continued to sue the government. Apparently, they want jaguars to repopulate the United State seven if jaguars don't wan! to. Last March, a federal district judge in Arizona ordered the Fish and Wildlife Service to revisit its 2006 determination on critical habitat. I)The facts haven't changed: there is still no area in the United States essential to the conservation of the jaguar. But, having asserted this twice already, the service, nowunder a new president, has bent to the tiresome litigation (诉讼). On Jan. 12, Fish and Wildlife officials, claimed to have evaluated new scientific information that had become available after the July 2006 ruling. They determined that it is now prudent to appoint critical habitat for the jaguar in the United States. J)This means that Fish and Wildlife must now also formulate a recovery plan for the jaguar. And since jaguars have not been able to reestablish themselves naturally over the past century, the government will likely have to go to significant expense to attempt to bring them back--especially if the cats have to be reintroduced. K)So why not do everything we can, at whatever cost, to bring jaguars back into the United States? To begin with, the American Southwest is, at best, marginal habitat for the animals. More important, there are better ways to help jaguars. South of our border, from Mexico to Argentina, thousands of jaguars live and breed in their true critical habitat. Governments and conservation groups (including the one I head) are already working hard to conserve jaguar populations and connect them to one another through an initiative called the Jaguar Corridor. L).The jaguars that now and then cross into the United States most likely come from the northernmost population of jaguars, in Sonora, Mexico. Rather than demand jaguars return to our country, we should help Mexico and other jaguar-range countries conserve the animals' true habitat it M )The recent move by the Fish and Wildlife Service means that the rare federal funds devoted to protecting wild animals will be wasted on efforts that cannot help save jaguars. It also stands to weaken the Endangered Species Act, because if critical habitat is redefined as any place where a species might ever have existed, and where you or I might want it to exist again, then the door is open for many other sense less efforts to bring back long-lost creatures. N)The Fish and Wildlife officials whose job is to protect the country's wild animals need to grow a stronger backbone--stick with their original, correct decision and save their money for more useful preservation work. Otherwise, when funds are needed to preserve all those small, ugly, non-charismatic endangered species at the back of the line, there may be no money left. 1. It is still a fact that there is no suitable place for jaguars to live safely in the United States. 2. The United States Fish and Wildlife Service should be more determined and saving for the conservation work. 3. Jaguars were regarded as endangered species because of their rare appearance at the United States-Mexico border. 4. Money was not spent effectively in helping save jaguars in the recent move by the Fish and Wildlife Service. 5. It can be inferred that the United States is not the best choice for jaguars to live from the evidence that they don't settle anywhere here.
精选考试类应用文档，如果您需要使用本文档，请点击下载，另外祝您生活愉快，工作顺利，万事如意！ 大学C语言考试题库及答案 姓名成绩 温馨提示：同学们，经过培训学习，你一定积累了很多知识，现在请认真、仔细地完成这张试题库吧。加油！ 一单项选择题库 1. 在C语言中，以 D 作为字符串结束标志 A)’\n’ B)’ ’ C) ’0’ D)’\0’ 2.下列数据中属于“字符串常量”的是（ A ）。 A.“a” B.{ABC} C.‘abc\0’ D.‘a’ 若干个字符构成字符串 在C语言中，用单引号标识字符；用双引号标识字符串 选项B，C，分别用{}和’’标识字符串 选项D，标识字符。 3、以下说法中正确的是（ C ）。 A、C语言程序总是从第一个定义的函数开始执行
B、在C语言程序中，要调用的函数必须在main( )函数中定义 C、C语言程序总是从main( )函数开始执行 D、C语言程序中的main( )函数必须放在程序的开始部分 4.下列关于C语言的说法错误的是（B ）。 A) C程序的工作过程是编辑、编译、连接、运行 B) C语言不区分大小写。 C) C程序的三种基本结构是顺序、选择、循环 D) C程序从main函数开始执行 5.下列正确的标识符是（C ）。 A.-a1 B.a[i] C.a2_i D.int t 6．下列C语言用户标识符中合法的是（B ）。 A)3ax B)x C)case D)-e2 E)union 7．下列四组选项中，正确的C语言标识符是（C ）。 A）%x B）a+b C）a123 D）123 8、下列四组字符串中都可以用作C语言程序中的标识符的是（A ）。 A、print _3d db8 aBc B、I\am one_half start$it 3pai C、str_1 Cpp pow while D、Pxq My->book line# His.age 9.C语言中的简单数据类型包括（D ）。 A、整型、实型、逻辑型 B、整型、实型、逻辑型、字符型 C、整型、字符型、逻辑型 D、整型、实型、字符型 10.在C语言程序中，表达式5%2的结果是 C 。
小学三年级奥数精品讲义 目录 第一讲加减法的巧算(一） 第二讲加减法的巧算（二） 第三讲乘法的巧算 第四讲配对求和 第五讲找简单的数列规律 第六讲图形的排列规律 第七讲数图形 第八讲分类枚举 第九讲填符号组算式 第十讲填数游戏 第十一讲算式谜（一) 第十二讲算式谜(二） 第十三讲火柴棒游戏（一） 第十四讲火柴棒游戏(二) 第十五讲从数量的变化中找规律 第十六讲数阵中的规律 第十七讲时间与日期 第十八讲推理
第十九讲循环 第二十讲最大和最小 第二十一讲最短路线 第二十二讲图形的分与合 第二十三讲格点与面积 第二十四讲一笔画 第二十五讲移多补少与求平均数第二十六讲上楼梯与植树 第二十七讲简单的倍数问题 第二十八讲年龄问题 第二十九讲鸡兔同笼问题 第三十讲盈亏问题 第三十一讲还原问题 第三十二讲周长的计算 第三十三讲等量代换 第三十四讲一题多解 第三十五讲总复习
第一讲加减法的巧算 森林王国的歌舞比赛进行得既紧张又激烈。选手们为争夺冠军，都在舞台上发挥着自己的最好水平。台下的工作人员小熊和小白兔正在统计着最后的得分。由于他们对每个选手分数的及时通报，台下的观众频频为选手取得的好成绩而热烈鼓掌，同时,观众也带着更浓厚的兴趣边看边猜测谁能拿到冠军。 观众的情绪也影响着两位分数统计者。只见分数一到小白兔手中,就像变魔术般地得出了答案。等小熊满头大汗地算出来时,小白兔已欣赏了一阵比赛,结果每次小熊算得结果和小白兔是一样的。小熊不禁问：“白兔弟弟,你这么快就算出了答案,有什么决窍吗?” 小白兔说:“比如2号选手是9３、９5、9８、96、８8、８9、87、９1、93、９1，去掉最高分98,去掉最低分87,剩下的都接近90为基准数,超过９0的表示成9０+‘零头数’，不足９0的表示成9０-‘零头数’。于是(９3+９5+96+8８+８9＋91＋９3+91）÷8=９０＋(３＋5+6―2―1＋１+3+１)÷8＝9０＋2=９2。你可以试一试。”?小熊照着小白兔说的去做,果然既快又对。这下小熊明白了，掌握了速算的技巧,在工作和生活中的作用很大。它不仅可以节省运算时间,更主要的是提高了我们的工作效率。 我们在进行速算时,要根据题目的具体情况灵活运用有关定律和法则，选择合理的方法。下面介绍在整数加减法运算中常用的几种速算方法。 例题与方法 第一题：巧算下面各题 ①３6+8７+64 ②99+１36＋101 ③1361＋97２＋６３9＋28 解答:①式=(36＋６４）＋87 =1００+87=187 ②式=（99+1０1）+136 =２0０+136＝３36 ③式＝（136１+639)＋（9７2＋28） =2０00+1000=３000