0.01+0.03+0.05+…+0.09++0.11+…0.97+0.99=1/100*(1+3+5+...+97+99)=1/100*(1+99)*50/2=250.01+0.03+0.05+…+0.09++0.11+…0.97+0.99=(0.01+0.99)+(0.03+0.97)+...+(0.49+0.51)=1*25=25