1/(1X3) + 1/(3X5) + 1/(5X7) + 1/(7X9) + … + 1/(97X99) + 1/(99X101)
=1/2x(1-1/3+1/3-1/5+...+1/99-1/101)
=1/2x(1-1/101)
=1/2x100/101
=50/101