（-270）*0.25+0.25*21.5+8.5*（-25%）=多少
问题描述：
（-270）*0.25+0.25*21.5+8.5*（-25%）=多少
答
=(1-1/51)*(1+1/51)*(1-1/52)*(1+1/52)*..............*(1-1/152)*(1+1/152)
=(50/51)*(52/51)*(51/52)*(53/52)*..............*(151/152)*(153/152)
中间约分
=(50/51)*(153/152)
=75/76
答
（-270）*0.25+0.25*21.5+8.5*（-25%）
=（-270）*0.25+0.25*21.5-8.5*0.25
=（-270+21.5-8.5）*0.25
=-257*0.25
=-64.25