125.5^2 - 2 * 125.5 * 25.5 + 1=125.5^2 - 2 * 125.5 * 25.5 + 25.5^2 - 25.5^2 + 1=(125.5-25.5)^2 - (25+0.5)^2 + 1=100^2 - 25^2 - 25 - 0.25 + 1 (其实还可以再分，不过最后还是要算的)=10000 - 625 - 25 - 0.25 + 1=9350.75
