(1+二分之一)乘(1-三分之二)乘(1+三分之二)乘(1-四分之一)计算
解,得：
(1+1/2)*(1-1/4)*[(1-2/3)*(1+2/3)]
==(1+1/2)*(1-1/4)*(1-4/9)
==(3/2)*(3/4)(5/9)
==(9/8)*(5/9)
==5/8