观察与计算. 1/2×3=1/2−1/3 1/3×4=1/3−1/4 1/4×5=1/4−1/5 试计算:1/6+1/12++1/30+…+1/2005×2006.

问题描述:

观察与计算.

1
2×3
1
2
1
3
     
1
3×4
1
3
1
4
      
1
4×5
1
4
1
5

试计算:
1
6
+
1
12
++
1
30
+…+
1
2005×2006

1
30
+…+
1
2005×2006

=
1
2×3
+
1
3×4
+
1
4×5
+…+
1
2005×2006

=
1
2
1
3
+
1
3
1
4
+
1
4
-
1
5
+…+
1
2005
-
1
2006

=
1
2
-
1
2006

=
501
1003