1/6x5-2/3
=5/6-2/3
=5/6-4/6
=1/61/6x(5-2/3)题目是这样的不是，我还以为是求差，这样写是求积答案是：1/6x5-1/6x2/3=5/6-1/9=15/18-2/18=13/18