6.42×0.9简便运算

如题所述

6.42×0.9
=6.42×(1-0.1)
=6.42-0.642
=5.778
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第1个回答  2016-05-19
6.42*0.9=642*9/(100*10)=(650-8)*9/1000=(65*9)/100-72/1000=65*(10-1)/100-0.072
=(650-65)/100-0.072=585/100-0.072=5.85-0.072=5.778
第2个回答  2016-05-19
=6*0.9+0.4*0.9+0.02*0.9
=5.4+0.36+0.018
=5.778