题目内容
0.125×32×25 | 128×99 |
|
(
| ||||||||||||||||||||||
|
|
10.9-1.6-3
|
| ||||||||||||||||||||||
2÷
|
6.5×99+6.5 | (
|
123×5.67+8.77×567 | ||||||||||||||||||||||
2-
|
2-
|
|
49×
| ||||||||||||||||||||||
(
|
9
|
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.
(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.
解答: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)10.9-1.6-3
,
=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
,
=(9+99+999+9999)+(
×4),
=9++(99+1)+(999+1)+(9999+1),
=9+100+1000+10000,
=11109.
=(0.125×8)×(4×25),
=1×100,
=100;
(2)128×99,
=128×(100-1),
=128×100-128×1,
=12800-128,
=12672;
(3)
32 |
3 |
2 |
3 |
=10
2 |
3 |
2 |
3 |
=10-3.14,
=6.86;
(4)(
5 |
6 |
3 |
4 |
5 |
12 |
9 |
5 |
=
5 |
6 |
5 |
12 |
3 |
4 |
5 |
12 |
9 |
5 |
=2-
9 |
5 |
9 |
5 |
=2;
(5)
4 |
7 |
3 |
8 |
1 |
8 |
5 |
7 |
=(
4 |
7 |
5 |
7 |
3 |
8 |
1 |
8 |
=
9 |
7 |
1 |
2 |
=1
11 |
14 |
(6)
1 |
2 |
1 |
3 |
2 |
3 |
=
1 |
2 |
1 |
2 |
=1;
(7)10.9-1.6-3
2 |
5 |
=10.9-(1.6+3.4),
=10.9-5,
=5.9;
(8)
1 |
4 |
4 |
3 |
1 |
2 |
=
1 |
4 |
5 |
6 |
=0.3;
(9)2÷
4 |
25 |
25 |
12 |
=2÷(
4 |
25 |
25 |
12 |
=2÷
1 |
3 |
=6;
(10)6.5×99+6.5,
=6.5×(99+1),
=6.5×100,
=650;
(11)(
1 |
2 |
1 |
3 |
1 |
6 |
=
1 |
2 |
1 |
3 |
1 |
6 |
=12+8+4,
=20+4,
=24;
(12)123×5.67+8.77×567,
=5.67×(123+877),
=5.67×1000,
=5670;
(13)2-
7 |
15 |
9 |
14 |
=2-0.3,
=1.7;
(14)2-
5 |
11 |
9 |
22 |
8 |
9 |
=2-(
10 |
9 |
8 |
9 |
=2-2,
=0;
(15)
3 |
4 |
1 |
2 |
3 |
8 |
=
3 |
4 |
1 |
2 |
3 |
8 |
=
3 |
4 |
1 |
8 |
=6;
(16)49×
5 |
48 |
=(48+1)×
5 |
48 |
=48×
5 |
48 |
5 |
48 |
=5+
5 |
48 |
=5
5 |
48 |
(17)(
2 |
3 |
1 |
8 |
9 |
19 |
=
19 |
24 |
10 |
19 |
=
5 |
12 |
(18)9
3 |
4 |
3 |
4 |
3 |
4 |
3 |
4 |
=(9+99+999+9999)+(
3 |
4 |
=9++(99+1)+(999+1)+(9999+1),
=9+100+1000+10000,
=11109.
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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