3.8*4.2+38*0.58怎么简便计算
问题描述：
3.8*4.2+38*0.58怎么简便计算
还有123+5.67+8.77*567怎么算.
答
3.8*4.2+38*0.58
=38*0.42+38*0.58
=38*(0.42+0.58)
=38*1
=38
123+5.67+8.77*567
=1.23*567+8.77*567
=567*(1.23+8.77)
=567*10
=5670