9.18-4.59-0.4=9.18-4.59-0.4-0.01+0.01=9.18-(4.59+0.4+0.01)+0.01=9.18-5+0.01=4.18+0.01=4.19
9.18-4.59-0.4=9.18-(4.59+0.4)=9.18-4.99=9.18-(5-0.01)=9.18-5+0.01=4.18+0.01=4.19