问题 解答题
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
答案

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

单项选择题
单项选择题