一、乘法分配律 (1.25-0.125)×8 (125+2.5)×0.8 3.72×3.5+6.28×3.5 =1.25×8-0.125×8 =125×0.8+2.5×0.8 =3.5×(3.5+6.28) =10-1 =1+1 =3.5×10 =9(正用) =2(正用) =35(逆用) 二、把其中一个因数分成两个数的和或差,再按乘法分配律