(1-100/1)(1-99/1)(1-98/1)...(1-4/1)(1-3/1)(1-2/1)

(1-100/1)(1-99/1)(1-98/1)...(1-4/1)(1-3/1)(1-2/1)

原式=(99/100)*(98/0)*...*(2/3)
分子分母一約分分1/100×2=1/50