问题 填空题
计算:
1
2
3
+2
3
4
+3
4
5
+…+1994
1995
1996
+1995
1996
1997
3
1
3
+5
2
4
+7
3
5
+…+3989
1994
1996
+3991
1995
1997
=______.
答案

1
2
3
+2
3
4
+3
4
5
+…+1994
1995
1996
+1995
1996
1997
3
1
3
+5
2
4
+7
3
5
+…+3989
1994
1996
+3991
1995
1997

=

(2-
1
3
)+(3-
1
4
)+(4-
1
5
)++(1995-
1
1996
)+(1996-
1
1997
)
(4-
2
3
)+(6-
2
4
)+(8-
2
5
)++(3990-
2
1996
)+(3992-
2
1997
)

=

1
2

故答案为:

1
2

单项选择题
判断题