《有理數(shù)加減混合運算》基礎(chǔ)的知識點

1、有理數(shù)加減混合運算知識點整理【知識點一】1有理數(shù)的加減乘除混合運算順序：如無括號則先算乘除，再算加減 ; 有括號的先算括號里面的。2算式中有小數(shù)的可化為分數(shù)，這樣利用分數(shù)乘除來約分，簡化計算。若有帶分數(shù)則化為假分數(shù)。3 熟練運用乘法交換律、乘法結(jié)合律和乘法分配率可以是計算簡便?！局R點二】有理數(shù)加法運算總是涉及兩個方面：一方面是確定結(jié)果的符號 , 另一方面是求結(jié)果的絕對值法則：同號兩數(shù)相加 , 取相同的符號 , 并把絕對值相加異號兩數(shù)相加 , 絕對值相等時和為 0, 絕對值不等時 , 取絕對值較大數(shù)的符號 , 并用較大的絕對值減去較小的絕對值一個數(shù)同 0 相加 , 仍得這個數(shù)有理數(shù)減法法則法則

2、：減去一個數(shù) , 等于加上這個數(shù)的相反數(shù)注：在運用減法法則時 , 注意兩個符號的變化 , 一是運算符號 , 減號變成加號 , 二是性質(zhì)符號 , 減數(shù)變成它的相反數(shù)有理數(shù)的加減混合運算加減混合運算可以通過減法法則, 將減法化加法 , 統(tǒng)一為加法運算步驟：減法化加法省略加號和括號運用加法法則, 加法運算律進行簡便運算【練習(xí)題】1、把 -+- 都統(tǒng)一轉(zhuǎn)化成加法運算, 即它還可以寫成省略加號的和的形式，即，讀作2、將下列式子寫成省略加號的和的形式，并說出它的兩種讀法： -+- -+-+43、 -11-9-7+6-8+10-7-3+-3124、某公路養(yǎng)護小組乘車沿南北方向公路巡視維護，某天從地出發(fā)， 約

3、定向南行駛為正，到收工時的行駛記錄如下：8，- ， 7， -4 ， -6 ， 13， 4， 12，-11問收工時，養(yǎng)護小組在地的哪一邊?距離地多遠 ?若汽車行駛毎千米耗油0 升，求從出發(fā)到收工共耗油多少升 ?答案1、-+ ， -+6-7+4 ， - 加 6 減 7 加 42、 37+2-3-24 -1-1-2+3+1+4 3、 -19 04、原點南邊18 米處3 升贈送以下資料英語萬能作文 (模板型）Along with the advance of the society more and more problems arebrought to our attention, one of w

4、hich is that.隨著社會的不斷發(fā)展，出現(xiàn)了越來越多的問題，其中之一便是_。As to whether it is a blessing or a curse, however, people take different attitudes.然而，對于此類問題，人們持不同的看法。 (Hold different attitudes持不同的看 ;Come up with different attitudes 有不同的看法 )As society develops, people are attaching much importance to.隨著社會的發(fā)展，人們開始關(guān)注.Peopl

5、e are attaching more and more importance to the interviewduring job hunting求職的過程中，人們慢慢意識到面試的重要性。As to whetherit is worthwhile., there is a long-runningcontroversial debate. It is quite natural that people from different backgrounds may have divergent attitudes towards it.關(guān)于是否值得 _的問題，一直以來爭論不休。當然，不同的人

6、對此可能持不同的觀點。In the process of modern urban development, we often findourselves in a dilemma.在都市的發(fā)展中，我們往往會陷入困境。Recently the phenomenon has aroused wide concern, some peopleare in alarm that.最近，這種現(xiàn)象引起了人們的廣泛關(guān)注，有人開始擔(dān)心_。The human race has entered a completely new stage in its history, with the increasingl

7、y rapid economic globalization and urbanization, more problems are brought to our attention.人類進入了一個歷史的嶄新的階段，經(jīng)濟全球化、都市化的速度不斷加快，隨之給我們帶來了很多問題。. plays such an important role that it undeniably becomes thebiggest concern of the present world, there comes a question, is it a blessing or a curse?"_顯得非常

8、重要而成為當今世界所關(guān)注的最大的問題，這是無可厚非的。不過，問題是："我們該如何抉擇 ?"Now we are entering a new era, full of opportunities and challenges, 現(xiàn)在我們正在進入一個充滿機會和挑戰(zhàn)的新時代。People from different backgrounds would put different interpretationson the same case.不同行業(yè)的人對同一種問題的解釋不盡相同。The controversial issue is often brought into pu

9、blic focus. People from different backgrounds hold different attitudes towards the issue.這中極具爭議性的話題往往很受社會的關(guān)注。不同的人對此問題的看法也不盡相同。When asked ., some people think. while some prefer.說到 _，有人認為 _，而另一些人則認為 _。Just as the saying goes: "so many people, so many minds". It is quiteunderstandable that v

10、iews on this issue vary from person to person.俗話說， ""。不同的人對此有不同的看法是可以理解的。To this issue, different people come up with various attitudes.對于這個問題，不同的人持不同的觀點。There is a good side and a bad side to everything, it goes withoutsaying that.萬事萬物都有其兩面性，所以，勿庸置疑，_。When it comes to ., most people belie

11、ve that ., but other peopleregard .as .提到 _問題，很多人認為 _，不過，一些人則認為_是_.When faced with., quite a few people claim that ., but otherpeople think as.提到 _問題，僅少數(shù)人認為 _，但另一些人則認為_。There is a public controversy nowadays over the issue of . Therewho criticize .argue that ., they believe that .,but people who fav

12、or .,on the other hand, argue that.目前，_問題爭議較大。批判 _的人認為 _，他們認為_，不過，另一方面，贊同_的人則認為 _。Some people are of the opinion that.有些人認為 _。Many people claim that.很多人認為 _。A majority of 絕大多數(shù)A large number of 很多人Some people contend that . has proved to bring many advantages(disadvantages)有些人認為 _有很多有利之處 (不利之處 )。Thos

13、e who argue for . say that .economic development of thecities.覺得 _的人認為， _ 城市的經(jīng)濟發(fā)展。Some people advocate that .有些人在堅持認為 _。They hold that . 他們認為 _。People, who advocate that ., have their sound reasons (grounds)堅持認為 _的人也有其說法 (依據(jù) )。Those who have already benefited from practicing it sing high praiseof it

14、.那些從中受益的人對此大家褒獎。Those who strongly approve of . have cogent reasons for it.強烈認同 _的人有很多原因 。Many people would claim that.有人會認為 _。People who support . give some or all of the following reasons.那些支持 _觀點的人列出了如下原因：_。But others hold the view that .但是，另外一些人則認為 _。觀點的用詞： Attitude, opinion,與其搭配的動詞以及詞組：Take,hav

15、e, come up with，set forth, put forward 等。But on the other hand, there are also quite a few people who strongly advocate that.,.不過，另一方面，也有少部分人堅持認為_。But people who are ., on the other hand , maintain that.不過，另一方面， _的人認為 _。However, there are a large number of people who hold a different view concerning

16、 this case.然而，很多人對此有不同的看法。問題用詞： Issue, phenomenon，后接介詞 , on, over 等。However, some others argue that. 然而，另一些人則認為_。However, there are also some others who contend that.然而，也有人認為 _。But other people set forth completely totally different argument concerning this case.不過，對于此，另一些人則持完全不同的觀點。Some people exam

17、ine this issue from another angle.有的人用另一角度來看這一問題。On the other hand, there are also many opponents who strongly .另一方面，也有很多反對的人，他們認為_。According to my personality and fondness, I would prefer . ratherthan.根據(jù)我的個性以及興趣， 我選擇 _而不會選擇 _。Personally, I side with the latter (former) opinion.就我個人而言，我支持后者(前者 )_。Pe

18、rsonally, I am in favor of the former point of view.就我個人而言，我較同意前一種看法。To my point of view 我認為Tomymind,theadvantagesfaroverweighthedrawbacks(disadvantages, shortcomings)我認為，優(yōu)點勝過缺點。For my part, I stand on side of the latter opinion that.就我而言，我較贊同后一種觀點_。As far as I am concerned, I am inclined to be on t

19、he side of the latter view.在我看來，我較同意后一種觀點。After a thorough consideration, for my part, I am in favor of thelatter view that.經(jīng)過深思熟慮，我較支持后一種看法，亦即_。If asked to make a decision, I would prefer.如果真的需要作出選擇，我寧愿_。展現(xiàn)問題篇問題的常用詞： question, problem, issueRecently, the issue of . has been brought into public focu

20、s.近來， _的問題引起了社會的廣泛關(guān)注。Now we are entering a brand new era full of opportunities and innovations, and great changes have taken place in people attitudes towards some traditional practice.現(xiàn)在我們進入了一個充滿機遇和創(chuàng)新的嶄新時代，很多人對某些傳統(tǒng)的看法也發(fā)生了很大改變。Recently the issue of whether or not . has been in the limelightand has a

21、roused wide concern in the public.近來，是否 _的問題已經(jīng)非常明確而且引起了社會的廣泛關(guān)注。The issue whether it is good or not to . has aroused a heateddiscussion all over the country._的利與弊已在全國范圍內(nèi)引起熱烈的討論。At present, some people think .while others claim .Both sideshave their merits.目前，一些人認為 _而另一些人則認為 _。其實，兩種觀點都其可取之處。People rarely reach an absolute consensus on such a controversial issue.對于這種極具爭議的話題，我們很難作出絕對的回答。People from different backgrounds would put different interpretations on the same case.不同行業(yè)的人對同一種問題的解釋不盡相同。The controversial issue is often brought into public focus. Peoplefrom different backgro