(1 / 100-1) (1 / 99-1) (1 / 98-1). (1 / 3-1) (1 / 2-1)

(1 / 100-1) (1 / 99-1) (1 / 98-1). (1 / 3-1) (1 / 2-1)

(1 / 100-1) (1 / 99-1) (1 / 98-1). (1 / 3-1) (1 / 2-1)
=(-99/100)(-98/99)(-97/98)(-96/97)…… (-2/3)(-1/2)
=-1/100