文档介绍:精编小学三年级奥数典型题测试卷(九) 乘除法的简便运算
(考试时间:100分钟 试卷满分:100分)
班级
—姓名
—学号
分数一
评卷人
得分
选择题(共3小题,满分6分,每小题2分)
(2分= 500-4
= 496
B、100 + 25 x4
= 100-100
=0
C> 88x4 + 37x4
= (88 + 37)x4
= 125x4
= 500
D、100x0x5 =0
故选:Co
(2 分)计算3x(lx2 + 2x3 + 3x4 + ... + 99xl00) = ( )
A. 97x98x99 B. 98x99x100 C. 99x100x101 D. 100x101x102
【解答】解:3x(lx2 + 2x3 + 3x4 + ...+ 99x100)
= 3x[lx(l + l) + 2x (2 + 1)+ 3x(3 + l) + ...+ 98x(98 + 1)+ 99x(99 + 1)]
= 3x[12 +1 + 22 + 2 + 32 + 3 + ... + 982 + 98 + 992 + 99]
= 3x[(F +22+32+... + 982 +992)+ (1 + 2 + 3 + ... + 98 + 99)]
= 3x[99x(99 + l)x(2x99 + l) 4-6 + (1 + 99)x994-2]
= 3x[99xl00xl99-6 + 100x99-2]
= 3x[33x50xl99 + 50x99]
= 3x33x100x101
= 99x100x101
= 999900
故选:Co
(2 分)11x19 + 12x18 + 13x17 + 14x16 = ( )
A. 860 B. 871 C. 875 D. 870
【解答】解:11x19+12x18+13x17 + 14x16 = (15-4)x(15 + 4) + (15-3)x(15 + 3) + (15-2)x(15 + 2)x(15-l)x(15 + l)
= 152 -42 +152 -32 +152 -22 +152 -I2
= 152 x4-(42 +32 +22 +12)
= 900 — 30
= 870
故选:£>o
填空题(共10小题,满分27分)
(2 分)计算:325x337 + 650x330+975 = 325000
【解答】解:325 x 337 + 650 x 330 + 975
= 325x337 + 325x(2x330) + 325x3
= 325*(337 + 2*330 + 3)
= 325x1000
= 325000
故答案为:325000.
(2 分)17x19 — 1001+77= 310 .
【解答】解:根据分析,原式= 17x19-1001+77
= 17*(20-1)-7*11x13 + 77
= 17x20-17-77x13-77
= 340—17—13
= 340-(17 + 13)
= 340-30
= 310.
故答案是:310.
(2 分)计算:(l + 2 + 3 + 4 + 5)x8= 120 .
【解答】解:(l + 2 + 3 + 4+5)x8
= 15x8
= 120
故答案为:120.
(2 分)计算:45x21 + 17x63= 2016 .
= 45x21 + 17x21x3
= 45x21 + 51x21
= 21x(45 + 51)
= 21x96
= 21x(100 — 4)
= 21x100-21x4
= 2100-84
= 2016
故答案为:2016.
(2 分)计算:23x10 — 18x7 + 8-2= 108
【解答】解:23x10-18x7 + 8-2
= 230-126 + 4
= 108
故答案为:108.
(2 分)计算:17x24 + 68x19= 1700 。
【解答】解:17x24 + 68x19
= 17x24 + 17x4x19
= 17x24 + 17x76
= 17x(24 + 76)
= 17x100
= 1700
故答案为:1700。
(4分)计算.
242x3 + 343 =;
555x2-654=;
857 寻7=;
16x48+ 50x16 +2x16=.
【解答】解:①242 x 3 + 343
= 726 + 343 = 1069
***@555x2-654
= 1110—654 = 456
③ 857+7 = 122...3
***@16x48 + 50x16 + 2x16
=