4

1

6

÷

5

8

-3

3

8

×1

1

15

=

25

6

×

8

5

-

26

8

×

16

15

=

20

3

-

52

15

=

48

15

=3

1

5

；

（1

2

3

-1

2

5

）÷（6-

2

7

）×4

2

7

=

4

15

÷

40

7

×

30

7

=

4

15

×

7

40

×

30

7

=

1

5

；

4

5

×25

5

8

-20

5

12

÷5+5

1

6

=

4

5

×

205

8

-

245

12

×

1

5

+5

1

6

=

41

2

-

49

12

+5

1

6

=

492

12

-

49

12

+5

2

12

=42

1

12

；

[1

1

5

×（1

1

2

-

2

3

）+5

3

5

]÷3

1

7

）

=[

6

5

×

5

6

+

8

5

]÷

22

7

=

13

5

×

7

22

=

91

110

．