9.4×4分之1+0.25×5分之3 =9.4×0.25+0.25×0.6 =（9.4+0.6）×0.25 =10×0.25 =2.5
5/9×3/4-1/5=5/12-1/5=25/60-12/60=13/60=60分之13
