最新GMAT数学考试中余数精讲.doc

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1、精品资料GMAT数学考试中余数精讲........................................精品资料 Introduction  (赶时间的童鞋可以略过。。。只是一些概念帮助童鞋们回忆余数~~~) Definition Ifxandyarepositiveintegers,thereexistuniqueintegersqandr,calledthequotientandremainder,respectively,suchthaty=divisor*quotient+remainder=xq+r;and0<=r

2、n15isdividedby6,thequotientis2andtheremainderis3since15=6*2+3. Noticethat0<=r

3、x. Forexample,12dividedby3yieldstheremainderof0since12isamultipleof3and12=3*4+0. Whenasmallerintegerisdividedbyalargerinteger,thequotientis0andtheremainderisthesmallerinteger. Forexample,7dividedby11hasthequotient0andtheremainder7since7=11*0+7 Thepossibleremainderswhenpositiveintegeryi

4、sdividedbypositiveintegerxcanrangefrom0tox-1. Forexample,possibleremainderswhenpositiveintegeryisdividedby5canrangefrom0(whenyisamultipleof5)to4(whenyisonelessthanamultipleof5). Ifanumberisdividedby10,itsremainderisthelastdigitofthatnumber.Ifitisdividedby100thentheremainderisthelast.....

5、...................................精品资料twodigitsandsoon. Forexample,123dividedby10hastheremainder3and123dividedby100hastheremainderof23. 1.  CollectionofMethods Method1：小数法（妹纸自己取的名字，包括后面的方法也都是妹纸取的~欢迎讨论） AwaythattheGMATwilltestremaindersiswhatyouwouldtypicallyjustdividebackintotheproble

6、mtodeterminethedecimals: 25/4=6remainder1 Dividethat1backby4toget0.25,sotheansweris6.25. Anynumberwitharemaindercouldbeexpressedasadecimal. Theremainderprovidesthedataafterthedecimalpoint,andthequotientgivesyouthenumbertotheleftofthedecimal........................................精品资料point

7、. Considerthisproblem(whichappearscourtesyofGMAC): Example： Whenpositiveintegerxisdividedbypositiveintegery,theremainderis9.Ifx/y=96.12,whatisthevalueofy? (A)96   (B)75   (C)48   (D)25   (E)12 Sol： Goingbacktotheconceptoftheremainder,theremainderof9iswhatwillgiveu