8分之17乘9分之4除以(1-6分之1)
=17/18除以5/6
=17/18*6/5
=17/15
15分之8除以8+15分之7乘8分之1
=8/15*1/8+7/15*1/8
=1/8*（8/15+7/15）
=1/8*1
=1/8
(25+5分之4)除以5分之1
=25*5+4/5*5
=125+4
=129