21/45=21÷3／45÷3=7/1591/39=91÷13/39÷13=7/3=2又3分之1144/12=144÷12/12÷12=12/1=1234/18=34÷2/18÷2=17/9=1又9分之836/108=36÷36/108÷36=1/3
7/15 2又1/3 1/12 9/17 1/3
