小学数学【乘法简便运算】专项计算题

小学数学【乘法简便运算】专项计算题


简介:
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 0.8×100.1 0.32×403 =0.8×(100+0.1) =0.32×(400+3) =0.8×100+0.8×0.1 =0.32×400+0.32×3 =80+0.08 =128+0.96 =80.08 =128.96 三、更改因数的小数点位置 6.66×3.3+0.666×67 46×57+23×86 =6.66×3.3+6.66×6.7 =46×57+46×43 =6.66×(3.3+6.1) =46×(57+43) =6.66×10 =46×100 =66.6 =4600