五年级数学・小数乘法简便运算・专项练习 一、拆加型 3.5×10.2 =3.5×(10+0.2) =3.5×10+3.5×0.2 =35+0.7 =35.7 三、顺展型 2.5×(4+0.8) =2.5×4+2.5×0.8 =10+2 =12 五、添“1”型 2.5×39+2.5 =2.5×39+2.5×1 =2.5×(39+1) =2.5×40 =100 七、移小数点 0.58×50.7+5.8×4.93 =5.8×5.07+5.8×4.93 =5.8×(5.07+4.93) =5.8×10 =58 二、拆减型 3.5×9.8 =3.5×(10-0.2) =3.5×10-3.5×0.2 =35-0.7 =34.3 四、逆合型 8.5×4.3+5.7×8.5 =8.5×(4.3+5.7) =8.5×10 =85 六、拆倍法 2.5×97+7.5 =2.5×97+2.5×3 =2.5×(97+3) =2.5×100 =250 八、拆分凑整 0.125×72 =0.125×8×9 =1×9 =9
