精英家教网 > 小学数学 > 题目详情
21
5
÷7×
5
9
15
2
×4÷
25
7
4
5
×
10
3
-
4
5
×
10
3
(1-
2
3
×
3
5
5
6
7
8
÷
3
8
-
1
8
÷
3
8
1
4
×
26
9
×
4
13
分析:此题考查在混合运算中有括号时,要先算括号里面的,再算括号外面的.
解答:解:
21
5
÷7×
5
9

=
3
5
×
5
9

=
1
3

15
2
×4÷
25
7

=30×
7
25

=
42
5

4
5
×
10
3
-
4
5
×
10
3

=0;
(1-
2
3
×
3
5
)×
5
6

=(1-
2
5
)×
5
6

=
1
2

7
8
÷
3
8
-
1
8
÷
3
8

=
7
3
-
1
3

=2,
1
4
×
26
9
×
4
13

=
1
3
点评:解决关键是在混合运算中,要按照运算顺序进行计算.
练习册系列答案
相关习题

科目:小学数学 来源: 题型:

(2011?万盛区模拟)
合理计算:
21
5
÷7×
5
9
1-
4
15
÷
4
5
+
2
3
1
4
+7.6+
3
4
+0.4;
12
23
÷8+
12
23
×
7
8
105×(
1
3
+
2
5
);   
 
1
2
+(
2
3
+
5
6
)×
4
15

查看答案和解析>>

科目:小学数学 来源: 题型:

1
2
×
2
5
=
1
5
1
5
5
7
÷
2
7
=
5
2
5
2
1
2
÷
1
4
=
2,
2,
1
3
=
9,
9,
10÷
1
8
×8=
640,
640,
5
14
×7=
5
2
5
2
3
5
+
2
5
=
1,
1,
100×
7
20
=
35,
35,
3
16
=
3
2
3
2
3
8
÷
3
8
×
5
6
=
5
6
5
6
1
4
+
1
3
=
7
12
7
12
1
4
=
0,
0,
2
9
=
2
9
2
9
7
12
÷
7
12
=
1,
1,
1
4
÷4×
1
4
=
1
16
1
16
5
6
×36=
30,
30,
3
10
=
10,
10,
10÷
5
9
=
18,
18,
6
5
÷
3
5
=
2,
2,
5
9
×
3
5
×3=
1,
1,
2
7
×14=
4,
4,
2
9
×
3
5
=
2
15
2
15
1
2
×3=
3
2
3
2
6
11
×
11
6
=
1,
1,
9×(2+
5
9
)=
23,
23,
70÷
7
10
=
100,
100,
19×
1
38
=
1
2
1
2
4
5
÷8%=
10,
10,
7
8
=
8
7
8
7
3
4
×
3
8
=
0
0

查看答案和解析>>

科目:小学数学 来源: 题型:

0.36÷12=
5
7
×
14
45
=
10×1.05=
9
20
÷9=
84÷0.7=
5-2.4=
5
16
=
4.37+6.63= 5÷25%=
1
2
×
3
5
=
2
15
+
3
15
=
7÷1.4= 72.8÷0.8=
4
5
-
1
3
=
16×0.001=
1
4
+
1
5
)×20=
1.25×
4
5
×8=
8.2+0.54+0.46=
5
9
-1.25=
125×0.8-100=

查看答案和解析>>

科目:小学数学 来源: 题型:

2.5+3.7= 217÷7= 70-34=
1.2×0.5= 1.3+27= 1.5÷0.5=
4.5-0.5= 25×0.4=
3
8
×
4
9
=
1
3
-
1
5
=
35×
4
7
=
2
15
+
3
5
=
3
8
=
2
5
+
1
2
=
8
9
-
5
9
=
7
10
÷
7
17
=

查看答案和解析>>

同步练习册答案