1(1/100)+2(1/100)+3(1/100)+...+99(1/100)简算

1(1/100)+2(1/100)+3(1/100)+。。。+99(1/100)=(1/100)*(1+2+3+。+99)=(1/100)*(1+99)*99/2=(1/100)*100*99/2=99/2