1又1/3-7/12+9/20-11/30+13/42-15/56,则n的负倒数是多少?

1又1/3-7/12+9/20-11/30+13/42-15/56

=1+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

n的负倒数是多少?是-1/n