( ):( )=0.45=27➗( )=40分之()
(9 ):(20 )=0.45=27➗(60 )=40分之(18)
(18 ):(40)=0.45=27➗(60 )=40分之(18)
(27 ):(60 )=0.45=27➗(60 )=40分之(18)
(36 ):(80 )=0.45=27➗(60 )=40分之(18)