每一个式子都用完全平方公式打开,得:原式=(1-1/2)×(1+1/2)×(1-1/3)×(1+1/3)×(1-1/4)×(1+1/4)…(1-1/99)×(1+1/99)×(1-1/100)×(1+1/100) =(1/2)×(3/2)×(2/3)×(4/3)×(3/4)×(5/4)×…×(98/99)×(100/99)×(99/100)×(101/100) =(1/2)×(101/100) =101/200