Question

巧算求和题1+2+3+4+5+6+7+8+7+6+5+4+3+2+1--------------------------

Answer 1

1+2+3+4+5+6+7+8+7+6+5+4+3+2+1=64

原式=8*8/(88888888*88888888)

=1/(11111111*11111111)

=1/(11111111^2)

=1/123456787654312