(78.6-0.786×25+75%×21.4)÷15×1997=_.
问题描述:
(78.6-0.786×25+75%×21.4)÷15×1997=______.
答
(78.6-0.786×25+75%×21.4)÷15×1997=[78.6-78.6×0.25+75%×(100-78.2)]÷15×1997;=(78.6-78.6×0.25+0.75×100-0.75×78.2)÷15×1997;=[(1-0.25-0.75)×78.6+0.75×100]÷15×1997;=75÷15×(2000...