1.25×1.2=1.25×（0.8+0.4）=1.25×0.8+1.25×0.4=1+0.5=1.5
1.25×1.2=1.25×(1+0.2)=1.25×1+1.25×2=1.25+0.25=1.5
1.25×1.2=1.25x4x0.3=5x0.3=1.5
