其实很简单,把分数化为假分数得:
=[5/3-(27/5-12/5)×1/3]÷8/9
=[5/3-15/5×1/3]÷8/9
=(5/3-3×1/3)÷8/9
=(5/3-1)÷8/9
=2/3×9/8
=3/4