3.8×2.8+28×0.12的简便方法解:3.8×2.8+28×0.12=3.8×2.8+2.8×1.2=2.8×(3.8+1.2)=2.8×5=14
3.8×2.8+28×0.12=3.8×2.8+2.8×1.2=2.8×(3.8+1.2)=2.8×5=14
=0.38*28+28*0.12=(0.38+0.12)*28=0.5*28=14
3.8*2.8+2.8*1.2=2.8*(3.8+1.2)=2.8*5=14