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苏科版数学七年级上册期中模拟试卷一、选择题1.比-1小2的数是(▲).A.3B.1C.-2D.-32.把(-2)-(+3)-(-5)+(-4)统一为加法运算,正确的是(▲).A.(-2)+(+3)+(-5)+(-4)B.(-2)+(-3)+(+5)+(-4)C.(-2)+(+3)+
(+5)+(+4)D.(-2)+(-3)+(-5)+(+4)3.下列各组数中,数值相等的是(▲).A.(-2)3和(-3)2B.-32和(-3)2C.-33和(-3)3D.-3×23和(-3×2)34.下列去括号正确的是(▲).A.-2(a+b)=-2a+bB.-
2(a+b)=-2a-bC.-2(a+b)=-2a-2bD.-2(a+b)=-2a+2b5.下列等式变形正确的是(▲).A.如果mx=my,那么x=yB.如果︱x︱=︱y︱,那么x=yC.如果-12x=8,那么x=-4D.如果x-2=y-2,那么x=y6.若967×8
5=p,则967×84的值可表示为(▲).A.p-967B.p-85C.p-1D.8584p7.如下四种图案的地砖,要求灰、白两种颜色面积大致相同,那么下面最符合要求的是(▲).8.下列四个数轴上的点A都表示数a,其中,一定满足
︱a︱>2的是(▲).A.①③B.②③C.①④D.②④二、填空题9.-13的相反数是▲,-13的倒数是▲.ABCD-2-222aaaaAAAA①②③④(第8题)10.比较大小:-2.3▲-2.4(填“>”或“<”或“=”).1
1.单项式-4πab2的系数是▲,次数是▲.12.研究表明,可燃冰是一种可替代石油的新型清洁能源,在我国某海域已探明的可燃冰储存量达150000000000m3,其中数字150000000000用科学记数
法可表示为▲.13.数轴上将点A移动4个单位长度恰好到达原点,则点A表示的数是▲.14.“减去一个数,等于加上这个数的相反数”用字母可以表示为▲.15.若5x6y2m与-3xn+9y6和是单项式,那么n-m的值为▲.16.若a-2b=3
,则2a-4b-5的值为▲.17.一米长的木棒,第1次截去一半,第2次截去剩下的一半,„„,如此截下去,第▲次截去后剩下的小棒长164米.18.若a<0,b>0,在a+b,a-b,-a+b,-a-b中最大的是▲.三、解答题1
9.计算:(1)(-8)+10-2+(-1);(2)12-7×(-4)+8÷(-2);(3)(12+13-16)÷(-118);(4)-14-(1+0.5)×13÷(-4)2.20.化简:(1)3x2-2xy+y2-3x2+3xy;(2)(7x2-3xy)-6(x2-1
3xy).21.先化简,再求值:5(3a2b-ab2)-(ab2+3a2b),其中a=-12,b=2.22.解方程:(1)2x+1=8-5x;(2)x+24-2x-36=1.23.某市出租车的计价标准为:行驶路程不超过3km收费10元,超过3km的部分按每千米1.8元收
费.(1)某出租车行程为xkm,若x>3km,则该出租车驾驶员收到车费▲元(用含有x的代数式表示);(2)一出租车公司坐落于东西向的宏运大道边,某驾驶员从公司出发,在宏运大道上连续接送4批客人,行驶路程记录如下(规定向东为正,向
西为负,单位:km).第1批第2批第3批第4批52-4-12①送完第4批客人后,该出租车驾驶员在公司的▲边(填“东或西”),距离公司▲km的位置;②在这过程中该出租车驾驶员共收到车费多少元?24.如图,长为50cm,宽为xcm的大长方
形被分割为8小块,除阴影A,B外,其余6块是形状、大小完全相同的小长方形,其较短一边长为acm.(1)从图可知,每个小长方形较长一边长是▲cm(用含a的代数式表示).(2)求图中两块阴影A,B的周长和(可以用含x的代数式表示).25.定义☆运算观察下列运算:
(+3)☆(+15)=+18(-14)☆(-7)=+21,(-2)☆(+14)=-16(+15)☆(-8)=-23,0☆(-15)=+15(+13)☆0=+13.(1)请你认真思考上述运算,归纳☆运算的法则
:两数进行☆运算时,同号▲,异号▲.特别地,0和任何数进行☆运算,或任何数和0进行☆运算,▲.(2)计算:(+11)☆[0☆(-12)]=▲.(3)若2×(2☆a)-1=3a,求a的值.axAB(第24题)26.【归纳】(1)观察下列各式的大小关系:|-
2|+|3|>|-2+3||-6|+|3|>|-6+3||-2|+|-3|=|-2-3||0|+|-8|=|0-8|归纳:|a|+|b||a+b|(用“>”或“<”或“=”或“≥”或“≤”填空)【应用】(2)根据上题中得出的结论,若|m|+|
n|=13,|m+n|=1,求m的值.【延伸】(3)a、b、c满足什么条件时,|a|+|b|+|c|>|a+b+c|.数学测试卷评分细则一、选择题二、填空题(每小题2分,共20分)9.13,-310.>11.-4π,312.1.5×101113.4或-414.a-b=a+(-b)1
5.-616.117.618.-a+b三、解答题(本大题共8小题,共64分)19.(16分)(1)解:原式=2-2+(-1)„„„„„„„„„„„„2分=0+(-1)„„„„„„„„„„3分=-1„„„„„„„„„„4分(2)解:原式=12-(-28)+(-4)„„„„„„„„„
„„„2分=12+28-4„„„„„„„„„„3分=36„„„„„„„„„„4分(3)解:原式=(12+13-16)×(-18)„„„„„„„„„„„„1分=(-9)+(-6)-(-3)„„„„„„„„„„3分=-12„„
„„„„„„„„4分(4)解:原式=-1-32×13÷16„„„„„„„„„„2分=-1-12×116„„„„„„„„„„3分=-3332„„„„„„„„„„4分20.(6分)(1)解:原式=3x2-3x2-2xy+3xy+y2„„„„„„„„„„1分=
xy+y2„„„„„„„„„„3分(2)解:原式=7x2-3xy-6x2+2xy„„„„„„„„„„1分=x2-xy„„„„„„„„„„3分题号12345678答案DBCCDADB21.(5分)解:原式=15a2b-5ab2-ab2-3a2b„„„„„„„„
„„1分=12a2b-6ab2„„„„„„„„„„3分当a=-12,b=2时原式=12×(-12)2×2-6×(-12)×22=6+12=18.„„„„„„„„„„5分22.(8分)(1)解:2x+5x=8-1„„„„„„„„„„2分7x=7„„„„„„„„„„3分x=1„„„„„„„
„„„4分(2)解:3(x+2)-2(2x-3)=12„„„„„„„„„„1分3x+6-4x+6=12„„„„„„„„„„2分-x=0„„„„„„„„„„„„3分x=0„„„„„„„„„„„„4分23.(6
分)(1)1.8(x-3)+10=1.8x+4.6„„„„„„„„„„2分(2)①西;9„„„„„„„„„„4分②13.6+10+11.8+26.2=61.6„„„„„„„„„„6分答:该出租车驾驶员共收到车费61.6元24.(6分)(1)(50-3a)„„
„„„„„„„„2分(2)2[50-3a+(x-3a)]+2[3a+x-(50-3a)]„„„„„„„„„„„„4分=2(50+x-6a)+2(6a+x-50)=4x„„„„„„„„„„6分25.(8分)(1)同号两数运算取正号,并把绝对值相加;„
„„„„„„„„„1分异号两数运算取负号,并把绝对值相加„„„„„„„„2分等于这个数的绝对值„„3分(2)23„„„„„„„„„„„„5分(3)①当a=0时,左边=2×2-1=3,右边=0,左边≠右边,所以a≠0;„„„„6分②当a﹥0时,2×(2+a)-1=3a,a=3
;„„„„„„„„7分③当a﹤0时,2×(-2+a)-1=3a,a=-5„„„„„„„„„„8分综上所述,a为3或-5注:自圆其说,前后一致就算对。如:学生填同号“绝对值相加”,异号“负数减去正数”。也可,但但第(3)问法则运用前后一致,要按此分类。第2个空填“异号时取绝对值较小
的数的符号,再把绝对值相加”也对,但第(3)问要按此分类。26.(9分)(1)≥„„„„„„„„„„„„2分(2)由上题结论可知,因为|m|+|n|=13,|m+n|=1,|m|+|n|≠|m+n|,所以
m、n异号.当m为正数,n为负数时,m-n=13,则n=m-13,|m+m-13|=1,m=7或6„„„„„„„„„„„„4分当m为负数,n为正数时,-m+n=13,则n=m+13,|m+m+13|=1,m=-7或-6„„„„„„„„„„„„6分综上所述,m为±
6或±7(3)分析:若按a、b、c中0的个数进行分类,可以分成四类:第一类:a、b、c三个数都不等于0①1个正数,2个负数,此时|a|+|b|+|c|>|a+b+c|②1个负数,2个正数,此时|a|+|
b|+|c|>|a+b+c|③3个正数,此时|a|+|b|+|c|=|a+b+c|,故排除④3个负数,此时|a|+|b|+|c|=|a+b+c|,故排除第二类:a、b、c三个数中有1个0【结论同第(1)问】①1个
0,2个正数,此时|a|+|b|+|c|=|a+b+c|,故排除②1个0,2个负数,此时|a|+|b|+|c|=|a+b+c|,故排除③1个0,1个正数,1个负数,此时|a|+|b|+|c|>|a+b+c|第三类:a、b、c三个数中有2个0①2个0,1个正数:此时|a|
+|b|+|c|=|a+b+c|,故排除②2个0,1个负数:此时|a|+|b|+|c|=|a+b+c|,故排除第四类:a、b、c三个数都为0,此时|a|+|b|+|c|=|a+b+c|,故排除综上所述:1个负数2个正数„„„„„„„„„„7分1个正数
2个负数„„„„„„„„„„„„8分1个0,1个正数和1个负数„„„„„„„„„„„„9分