观察下面算式,你发现了什么? 1/2=1/1×2=1-1/2 1/6=1/2×3=1/2-1/3 1/12=1/3×4=1/3-1/4 请你计算. 1/2+1/6+1/12+1/20+1/30+1/42+1/56=

问题描述:

观察下面算式,你发现了什么?

1
2
=
1
1×2
=1-
1
2
   
1
6
=
1
2×3
=
1
2
-
1
3
      
1
12
=
1
3×4
=
1
3
-
1
4

请你计算.
1
2
+
1
6
+
1
12
+
1
20
+
1
30
+
1
42
+
1
56
=

1
2
+
1
6
+
1
12
+
1
20
+
1
30
+
1
42
+
1
56

=1-
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-
1
8

=
7
8