1/2+(1/4+3/4)+(1/6+3/6+5/6)……+(1/98+3/98+……+97/98)
=1/2+1+3/2+2+5/2+...+49/2
=(1/2)*(1+2+3+...+49)
=(1/2)*(1+49)*49/2
=1225/2
1/2+(1/4+3/4)+(1/6+3/6+5/6)……+(1/98+3/98+……+97/98)
=1/2+1+3/2+2+5/2+...+49/2
=(1/2)*(1+2+3+...+49)
=(1/2)*(1+49)*49/2
=1225/2