(1+2/3)*(1-2/3)*(1+2/5)*(1-2/5)*.*(1+2/99)*(1-2/99)
=(1+2/3)*(1+2/5)*.*(1+2/99)*(1-2/3)*(1-2/5)*.*(1-2/99)
=5/3*7/5*.*101/97*1/3*3/5*.*97/99
=1/3*101*1/99
=101/297
(1+2/3)*(1-2/3)*(1+2/5)*(1-2/5)*.*(1+2/99)*(1-2/99)
=(1+2/3)*(1+2/5)*.*(1+2/99)*(1-2/3)*(1-2/5)*.*(1-2/99)
=5/3*7/5*.*101/97*1/3*3/5*.*97/99
=1/3*101*1/99
=101/297