题目内容
计算下面各题,怎样算简便就怎样算.
9.43-2.6+8.57-3.4
12×(
+
-
)
375+450÷18×2
5(
+
)÷
+
.
9.43-2.6+8.57-3.4
12×(
1 |
4 |
1 |
6 |
1 |
3 |
375+450÷18×2
5(
4 |
5 |
1 |
4 |
7 |
3 |
7 |
10 |
分析:(1)根据加法交换律和结合律以及减法的性质进行简算;
(2)根据乘法分配律进行简算;
(3)先算除法,再算乘法,最后算加法;
(4)先算小括号里面的加法,再算除法,最后算括号外面的加法.
(2)根据乘法分配律进行简算;
(3)先算除法,再算乘法,最后算加法;
(4)先算小括号里面的加法,再算除法,最后算括号外面的加法.
解答:解:
(1)9.43-2.6+8.57-3.4,
=(9.43+8.57)-(2.6+3.4),
=18-6,
=12;
(2)12×(
+
-
),
=12×
+12×
-12×
,
=3+2-4,
=5-4,
=1;
(3)375+450÷18×25,
=375+25×25,
=375+625,
=1000;
(4)(
+
)÷
+
,
=
÷
+
,
=
+
,
=
.
(1)9.43-2.6+8.57-3.4,
=(9.43+8.57)-(2.6+3.4),
=18-6,
=12;
(2)12×(
1 |
4 |
1 |
6 |
1 |
3 |
=12×
1 |
4 |
1 |
6 |
1 |
3 |
=3+2-4,
=5-4,
=1;
(3)375+450÷18×25,
=375+25×25,
=375+625,
=1000;
(4)(
4 |
5 |
1 |
4 |
7 |
3 |
7 |
10 |
=
21 |
20 |
7 |
3 |
7 |
10 |
=
9 |
20 |
7 |
10 |
=
23 |
20 |
点评:此题主要考查分数、整数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.
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