问题 解答题
计算下面各题.
A、2
1
2
÷
1
4
×1
2
5

B、3
2
9
+5
1
4
+4
3
4
+4
7
9

C、18.4-(4
1
3
-1
3
4
÷
1
2
)÷1
2
3

D、
1
2
+
1
6
+
1
12
+
1
20
+
1
30
+
1
42

E、3
4
7
×(7
1
3
+1
4
7
7
25
÷1
1
21
答案

A、2

1
2
÷
1
4
×1
2
5

=

5
2
×4×
7
5

=14;

B、3

2
9
+5
1
4
+4
3
4
+4
7
9

=(3

2
9
+4
7
9
)+(5
1
4
+4
3
4
),

=8+10,

=18;

C、18.4-(4

1
3
-1
3
4
÷
1
2
)÷1
2
3

=18.4-(4

1
3
-
7
2
)÷1
2
3

=18.4-

5
6
×
3
5

=18.4-0.5,

=17.9;

D、

1
2
+
1
6
+
1
12
+
1
20
+
1
30
+
1
42

=1-

1
2
+
1
2
-
1
3
+
1
3
-
1
4
+
1
4
-
1
5
+
1
5
-
1
6
+
1
6
-
1
7

=1-

1
7

=

6
7

E、3

4
7
×(7
1
3
+1
4
7
7
25
÷1
1
21

=

25
7
×
7
25
×(7
1
3
+1
4
7
)×
21
22

=(7

1
3
+1
4
7
)×
21
22

=

22
3
×
21
22
+
11
7
×
21
22

=7+

3
2

=8

1
2

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