112-256+3112-41920+5130-64142+7156-87172+9190=______．

题型：填空题难度：一般来源：不详

1

1

2

-2

5

6

+3

1

12

-4

19

20

+5

1

30

-6

41

42

+7

1

56

-8

71

72

+9

1

90

=______．

答案

原式=

3

2

-3+

1

6

+3+

1

12

-5+

1

20

+5+

1

30

-7+

1

42

+7+

1

56

-9+

1

72

+9+

1

90

=2-

1

2

+

1

6

+

1

12

+

1

20

+

1

30

+

1

42

+

1

56

+

1

72

+

1

90

=2-

1

2

+

1

2

-

1

3

+

1

3

-

1

4

+

1

4

-

1

5

+

1

5

-

1

6

+

1

6

-

1

7

+

1

7

-

1

8

+

1

8

-

1

9

+

1

9

-

1

10

=2-

1

10

=

19

10

．