Well, if he had 21 pieces, the question becomes "Did he make them all?" If yes, he made at least 21 pieces. He might have made more than 21 and given some away by the time someone counted to determine that he had 21. If he didn't make them all, perhaps he was given some of them, then he made less than 21 pieces. But there is no way to tell exactly how many. The only thing that you can say for sure is that he made no fewer than 2 pieces. The lower limit comes from the fact that the problem opens with the statement: "Jason made pieces of rope that were 2/3 yard long." "Jason made..." demands that the number be larger than zero, and "pieces" being plural demands that the number be 2 or greater.
John
My calculator said it, I believe it, that settles it