用简便方法计算:(0.75x42.6-0.574x25+57.4)/3
问题描述：
用简便方法计算:(0.75x42.6-0.574x25+57.4)/3
答
(0.75x42.6-0.574x25+57.4)/3 =(0.75x42.6-57.4x0.25+57.4x1)/3 =(0.75x42.6+57.4x1-57.4x0.25)/3 =[0.75x42.6+57.4x(1-0.25)]/3 =[0.75x42.6+57.4x0.75]/3 =0.75x(42.6+57.4)/3 =0.75x100/3 =75/3=25