解析:依题意可得,
(81÷123)×(123÷9)
=81÷123×123÷9
=81÷9
=9
(81÷123)×(123÷9)=81÷123×123÷9=9
(81÷123)×(123÷9)=81÷123x123÷9=81÷9=9