1/42+1/56+1/72+1/90+1/110+1/132问：这道题应该怎么简算?求详解

Question

1/42+1/56+1/72+1/90+1/110+1/132 问：这道题应该怎么简算?求详解

Answer 1

=1/(6x7)+1/(7x8)+1/(8x9)+.*1/(11x12)
=(1/6-1/7)+(1/7-1/8)+...+(1/11-1/12)
=1/6-1/12
=1/12
,
马到成功!