(1+1/1*3)*(1+1/2*4)*(1+1/3*5).(1+1/98*100)*(1+1/99*101)
=(2*2)/(1*3)*3*3/(2*4)*(4*4)/(3*5)*.*(99*99)/(98*100)*(100*100)/(99*101)
=2/1*(100/101)
=200/101