0.04×99-0.04=0.04×(99-1)=0.04×98=0.04×(100-2)=0.04×100-0.04×2=4-0.08=3.92
=0.04*(99-1)=0.04*(100-2)=0.04*100-0.04*2=4-0.08=3.92
