Question

用简便方法计算下面各题．0.25×3.2×0.125 &nb...

用简便方法计算下面各题．0.25×3.2×0.125 2.46×19-0.46×19 34.5×102 9.8×9.9+0.98．

Answer 1

①0.25×3.2×0.125 =（0.25×0.4）×（8×0.125） =0.1×1 =0.1； ②2.46×19-0.46×19 =（2.46-0.46）×19 =2×19 =38；
③34.5×102  =34.5×（100+2） =34.5×100+34.5×2 =3450+69 =3519；

④9.8×9.9+0.98
=0.98×99+0.98
=0.98×（99+1）
=98．