初一数学上每周一练01.12
初一数学周周练(01.12)
一、细心填一填(本大题满分26分,每空2分) 班级 姓名 11
1.-3的倒数是,-的相反数是
24
2.绝对值等于它本身的数是3.计算:
3
平角= 度,22︒50’+23︒40’= 4
4.若3a 4b m -n 和2a m b 是同类项,则mn +15.若一个角的余角等于31︒,则它的补角等于6.已知M =2x 2y -3xy 2+x +y 2, N =4x 2y -5xy 2-x +1则M+N中的次数为3的项的系数之和等于7.一支铅笔和一支钢笔的原价分别是a 元和b 元(b>a),若铅笔降价10%,而钢笔提价10%,则
B 现在买一支铅笔和一支钢笔比原来多付 元 C a 8.如图∠AOB 中,OD 是∠BOC 的平分线,OE 是∠AOC 的 E
平分线,若∠AOB=150︒,则∠EOD= 度 b
O 9.如图,已知直线a 、b 、c 、d ,a ∥b ,c ⊥d ,∠1=40︒, 第9题
第8题
d
则∠2= 度
3579
10.找规律,并填上一个合适的数:-, , -, ,
24816
正
左
视
视
图图
11.右图是若干个相同的长方体堆成的物体的三视图,若每 俯
23视
个长方体的体积是5cm ,则该物体的体积是 cm .
图
二、精心选一选(本大题满分36分,每小题3分) 12.下列各数中最大的数是 ······································································································· ( )
(A)(-3-2) 3 (B)(-3) ⋅(-1) 4
1
(C)(-3) ÷
21
(D)(-3) ⋅(-) 3
3
n n +1
13.N 为偶数,则(-2) +(-2) 所得结果是 ············································································· ( )
(A)2n (B)-1 (C)-2 (D)-2n 14.若|a |=3, |b |=2,且a 0,则a+b的值等于 ··························································· ( ) (A)5 (B)-1 (C)-5 (D)1 15.时刻3׃30时,钟面上时针与分针的夹角是 ········································································ ( )
(A)85︒ (B)75︒ (C)70︒ (D)60︒ 16.将线段AB 延长至C ,再将线段AB 反向延长至D ,则图中共有线段 ···························· ( )
(A)6 (B)5 (C)4 (D)3 17.已知M 、N 、P 是同一直线上的三个点,MN=a ,NP=b ,(a>b),则MP 的距离等于 ··· ( )
(A)a+b (B)a -b (C)b -a (D) a+b或a -b 18.在下列图形中,线段PQ 表示点P 到直线a 的距离是 ······················································ ( ) Q
Q P
(B ) A ) (C ) (D )
19.下列说法正确的是 ··············································································································· ( )
(A)长方体的平面展开图是长方形 (B)两直线与第三条直线相交的同位角相等 (C)角120︒的余角的度数为60︒ (D)对顶角相等 20.一个数保留有效数字是31.0那么这个数可能是 ································································ ( )
(A)31.13 (B)31.06 (C) 30.96 (D)30.946 21.已知x 2+2x +5的值是7,则代数式3x 2+6x -8的值为 ····················································· ( ) (A)-2 (B)0 (C)2 (D)4 22.下图中不可能成为正方体的平面展开图的是 ····································································· ( )
(C )
23.下列事件中不可能发生的事件是 ························································································ ( )
(A) 投一枚骰子出现偶数点 (B) 若x 为有理数,则x 2
(D)袋中有100个白球和一个红球,从袋中摸出一个球正好是红球
三、认真答一答
11111
24.计算(-3) 4÷(1) 2-5⨯(-) +|-32-9|+⨯() 2 (本题满分5分)
22632
25.(本题满分5分)已知代数式(1)请化简,并求当x=-2,y =
1231
x -(2x -y 2+3xy ) +(x -x 2+y 2) +2xy 2323
1
时代数式的值;(2)若x 、y 是互为相反数,请你判断代数式的2
值是 ············································································································································· ( )
(A)恒大于0 (B)恒小于0 (C)恒大于或等于0 (D)恒小于或等于0
26.简答题:(本题满分12分,每小题4分)
(1) 如图,①用代数式表示图中阴影部分的面积;
②当a=4cm,b=3cm时,计算阴影部分的面积(π取3.14,结果精确到0.1)
(2)已知9×0+1=1;9×1+2=11;9×2+3=21;9×3+4=31;9×4+5=41;„通过观察这些等式,根据你发现的运算规律,请回答:第10个式子的值是 ; 第n 个(n 为正整数)式子的值为 .
(3)下图为某地区某一天室外气温整点统计情况的折线图:
请观察折线统计图,并回答下列问题: ①全天温差为
度;
②一天中温度在16︒C —24︒C 之间的约有 小时. 27.(本题满分5分)今有一岛P 位于A 地的北偏东65︒,B 地的南偏东75︒处。 (1) 请你在图中准确作出小岛P 的位置;
(2) 若甲,乙两组考察队队员分别从A ,B 两地同时出发登陆小岛,且甲组速度是乙组速度的2
倍,请你判定领先登上小道的小组是 。
北
B (乙)
东 北 东
A (甲)
28.(本题满分5分)已知:如图四边形ABCD 中,DC ∥AB ,AC 平分∠DAB ,∠ACB=
7
∠ACD ,3
∠D=120︒,求∠ABC 的度数。
29.(本题满分5分)如图,已知B ,A ,E 三点在同一直线上,AD ⊥BC ,垂足为D ,EG ⊥BC ,垂足为G ,交AC 于 F ,且∠1=∠2,请你说明AD 平分∠BAC 。
四、仔细想一想(本题满分6分)
30
10×8的方格组成,若将图案中的图形进
行平移,同时保持图形的完整,则可得到不同的图案,因而请思考下列问题:
(1)如果将图案中的图形进行向左或向右平移若干格,则可得到 (2)如果将图案中的图形进行向左,右,上,下任意平移若干格,则可得到不同的图案;
(3m ×n (m>5,n>5)的方格组成。且将图案中的图形进行向左、右、 个与原图案不同的图案。