1/2+2/3+3/4+4/5+...97/98+98/99+99/100=(1-1/2)+(1-1/3)+(1-1/4)+……+(1-1/100)=100-(1/2+1/3+1/4+1/5+...1/98+1/99+1/100)=100-(1+2+3……+100)/100=100-5050/100=49.5