问题 解答题
2
5
-
2
5
×
3
4
÷
5
2
2-
5
9
-
4
15
÷
3
5
2
5
×
5
9
+
2
5
÷
9
4
6
7
÷(
4
9
+
2
3
×
5
6
5
6
+
3
8
)×48
8
17
÷23+
1
23
×
9
17
答案

(1)

2
5
-
2
5
×
3
4
÷
5
2

=

2
5
-
3
10
÷
5
2

=

2
5
-
3
25

=

7
25

(2)2-

5
9
-
4
15
÷
3
5

=2-

5
9
-
4
9

=2-(

5
9
+
4
9
),

=2-1,

=1;

(3)

2
5
×
5
9
+
2
5
÷
9
4

=

2
5
×
5
9
+
2
5
×
4
9

=

2
5
×(
5
9
+
4
9
),

=

2
5
×1,

=

2
5

(4)

6
7
÷(
4
9
+
2
3
×
5
6
),

=

6
7
÷(
4
9
+
5
9
),

=

6
7
÷1,

=

6
7

(5)(

5
6
+
3
8
)×48,

=

5
6
×48+
3
8
×48,

=40+18,

=58;

(6)

8
17
÷23+
1
23
×
9
17

=

8
17
×
1
23
+
1
23
×
9
17

=

1
23
×(
8
17
+
9
17
),

=

1
23
×1,

=

1
23

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