题目内容
0.125×32×25 | 128×99 | -(3.14+) | (-)÷+ |
+++ | +÷ | 10.9-1.6- | ÷(-) |
2÷÷ | 6.5×99+6.5 | (++)×24 | 123×5.67+8.77×567 |
2-× | 2-÷- | ÷(1--) | 49× |
(+)×(1-) | +++. |
解:(1)0.125×32×25,
=(0.125×8)×(4×25),
=1×100,
=100;
(2)128×99,
=128×(100-1),
=128×100-128×1,
=12800-128,
=12672;
(3)-(3.14+),
=10-3.14-,
=10-3.14,
=6.86;
(4)(-)÷+,
=-÷+,
=2-+,
=2;
(5)+++,
=(+)+(+),
=+,
=1;
(6)+÷,
=+,
=1;
(7)10.9-1.6-,
=10.9-(1.6+3.4),
=10.9-5,
=5.9;
(8)÷(-),
=÷,
=0.3;
(9)2÷÷,
=2÷(×),
=2÷,
=6;
(10)6.5×99+6.5,
=6.5×(99+1),
=6.5×100,
=650;
(11)(++)×24,
=×24+×24+×24,
=12+8+4,
=20+4,
=24;
(12)123×5.67+8.77×567,
=5.67×(123+877),
=5.67×1000,
=5670;
(13)2-×,
=2-0.3,
=1.7;
(14)2-÷-,
=2-(+),
=2-2,
=0;
(15)÷(1--),
=÷(),
=,
=6;
(16)49×,
=(48+1)×,
=48×+1×,
=5+,
=5;
(17)(+)×(1-),
=×,
=;
(18)+++,
=(9+99+999+9999)+(×4),
=9++(99+1)+(999+1)+(9999+1),
=9+100+1000+10000,
=11109.
分析:(1)化32=8×4,再运用乘法结合律解答,
(2)(4)(10)(11)(12)(16)运用乘法分配律解答,
(3)(7)(14)依据减法的性质解答,
(5)运用加法交换律和结合律解答,
(6)(8)(13)(15)(17)依据四则运算计算方法解答,
(9)运用除法的性质解答,
(18)根据整数部分与整数部分,分数部分与分数部分相加解答.
点评:本题主要考查了学生运用四则运算计算方法,以及简便算法解决问题的能力
=(0.125×8)×(4×25),
=1×100,
=100;
(2)128×99,
=128×(100-1),
=128×100-128×1,
=12800-128,
=12672;
(3)-(3.14+),
=10-3.14-,
=10-3.14,
=6.86;
(4)(-)÷+,
=-÷+,
=2-+,
=2;
(5)+++,
=(+)+(+),
=+,
=1;
(6)+÷,
=+,
=1;
(7)10.9-1.6-,
=10.9-(1.6+3.4),
=10.9-5,
=5.9;
(8)÷(-),
=÷,
=0.3;
(9)2÷÷,
=2÷(×),
=2÷,
=6;
(10)6.5×99+6.5,
=6.5×(99+1),
=6.5×100,
=650;
(11)(++)×24,
=×24+×24+×24,
=12+8+4,
=20+4,
=24;
(12)123×5.67+8.77×567,
=5.67×(123+877),
=5.67×1000,
=5670;
(13)2-×,
=2-0.3,
=1.7;
(14)2-÷-,
=2-(+),
=2-2,
=0;
(15)÷(1--),
=÷(),
=,
=6;
(16)49×,
=(48+1)×,
=48×+1×,
=5+,
=5;
(17)(+)×(1-),
=×,
=;
(18)+++,
=(9+99+999+9999)+(×4),
=9++(99+1)+(999+1)+(9999+1),
=9+100+1000+10000,
=11109.
分析:(1)化32=8×4,再运用乘法结合律解答,
(2)(4)(10)(11)(12)(16)运用乘法分配律解答,
(3)(7)(14)依据减法的性质解答,
(5)运用加法交换律和结合律解答,
(6)(8)(13)(15)(17)依据四则运算计算方法解答,
(9)运用除法的性质解答,
(18)根据整数部分与整数部分,分数部分与分数部分相加解答.
点评:本题主要考查了学生运用四则运算计算方法,以及简便算法解决问题的能力
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