[(5又12分之7-3又36分之17)(1.9-0.5)]X9分之19
=[(5+7/12-3-17/36)*1.4]*19/9
=(2+21/36-17/36)*9/5*19/9
=（2+1/9)*19/5
=19/9*19/5
=361/45
=8又1/45