0.72×1.2×1.25×2.5=(0.8×0.9)×(1+0.2)×1.25×2.5=0.8×1.25×0.9×[(1+0.2)×2.5]=1×0.9×(1×2.5+0.2×2.5)=0.9×(2.5+0.5)=0.9×3=2.7