类型一:连乘法(乘法交换律和结合律的运用) 例:× × ×17× × × ×17 = ×( ×) =× ×17 =(× )×(×17) =× =3×17 = ×3 = =51 =2 类型二:乘法分配律的顺展型 例:27×( - ) ( + )× ( + - )×24 =27× - ×27 = × + × =×24+ ×24- ×24 =24-18 =1+ =3+6-4 =6 = =5