0.64*0.25+0.75=0.16x4x0.25+0.75=0.16+0.75=0.91
即0.8^2X0.5^2+0.75=(0.8X0.5)^2+0.75=0.4^2+0.75=0.16+0.75=0.91
等于0.16*4*0.25+0.75=0.91