David had 5/9 of an apple pie. He ate 1/3 of it. What fraction of David’s pie was left?

Answer 1

If by "David's pie" you mean the 5/9 of a whole pie that he had, then 2/3 of it is left

If you mean the whole pie, then 2/3 * 5/9 = 10/27

In math, there is usually a right answer, but you have to be very clear about the question.