用简便方法计算下面各题,(14.2+14.1+14.4+14.3+14.5)*0.2用地等式,

问题描述:

用简便方法计算下面各题,(14.2+14.1+14.4+14.3+14.5)*0.2用地等式,

(14.2+14.1+14.4+14.3+14.5)*0.2
=(14*5+0.1+0.2+0.3+0.4+0.5)*2
=(70+1.5)*2
=140+3
=143