问题 解答题
7
9
÷21×
3
4

13
14
+
5
7
÷
13
14

1÷(
2
5
+2.1×
2
3
答案

(1)

7
9
÷21×
3
4

=

1
27
×
3
4

=

1
36

(2)(

13
14
+
5
7
÷
13
14

=

13
14
×
14
13
+
5
7
×
14
13

=1+

10
13

=1

10
13

(3)1÷(

2
5
+2.1×
2
3
),

=1÷(

2
5
+1.4),

=1÷1.8,

=

5
9

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