2.25×1.8+1.25×0.18＝2.25×1.8＋0.125×1.8＝1.8×（2.25＋0.125）＝1.8×2.375＝4.275
2.25x1.8+1.25x0.18=2.25*0.18*10+1.25*0.18=0.18(2.25+10+1.25)=0.18*13.5=2.43
=2.25*1.8+(2.25-1)*0.18=2.25(1.8+0.18)-0.18=4.275
