(0.1+0.2-0.3)*(0.4-0.5)=0
(0.1+0.2-0.3)*(0.4+0.5)=0
(0.1+0.2-0.3)/(0.4-0.5)=0
(0.1+0.2-0.3)/(0.4+0.5)=0