计算:711/6×6/7+611/5×5/6+511/4×4/5+411/3×3/4+311/2×2/3=_.

问题描述:

计算:71

1
6
×
6
7
+61
1
5
×
5
6
+51
1
4
×
4
5
+41
1
3
×
3
4
+31
1
2
×
2
3
=______.

71

1
6
×
6
7
+61
1
5
×
5
6
+51
1
4
×
4
5
+41
1
3
×
3
4
+31
1
2
×
2
3

=(70+
7
6
6
7
+(60+
6
5
5
6
+(50+
5
4
4
5
+(40+
4
3
3
4
+(30+
3
2
2
3

=60+1+50+1+40+1+30+1+20+1,
=205.
故答案为:205.