（0.75*57.4-0.574*25+57.4）/3 用简便方法
问题描述：
（0.75*57.4-0.574*25+57.4）/3 用简便方法
答
（0.75*57.4-0.574*25+57.4）/3
=(0.75*57.4-57.4*0.25+57.4)/3
=[57.4*(0.75-0.25+1)]/3
=57.4*1.5/3
=57.4*0.5
=28.7