=54*(13/14*7/13)=54*1/2=27
=12/12*(14/17*17/14)*13/24=1*1*13/24=13/24
=(21/22*22/23)*(24/25*23/24)=21/23*23/25=21/25
=54*(13/14*7/13)=54*1/2=27
=12/12*(14/17*17/14)*13/24=1*1*13/24=13/24
=(21/22*22/23)*(24/25*23/24)=21/23*23/25=21/25