用简便方法计算下面各题． ①4.8×0.25 ②2.33×0.5×4 ③1.5×105 ④1.2×2.5+0.8×2.5．
问题描述：
用简便方法计算下面各题．
| ①4.8×0.25 | ②2.33×0.5×4 | ③1.5×105 | ④1.2×2.5+0.8×2.5． |
答
①4.8×0.25
=1.2×（4×0.25）
=1.2×1
=1.2
②2.33×0.5×4
=2.33×（0.5×4）
=2.33×2
=4.66
③1.5×105
=1.5×（100+5）
=1.5×100+1.5×5
=150+7.5
=157.5
④1.2×2.5+0.8×2.5
=（1.2+0.8）×2.5
=2×2.5
=5．