Shalom Bumy,

Tosfos initially wanted to infer something from the fact that Rebbi Yehoshua ben Levi said, "Shishim v'Achas" (sixty-one) and did not say "Shishim v'Hi" (sixty and it).

Tosfos' understanding was as follows. If sixty-one, including the forbidden egg, would have been sufficient, it would have been more precise to say "Shishim v'Hi," meaning sixty including the Isur. That wording would indicate that the total number, including the forbidden egg, is sixty-one. It is the same number of words and more exact. Since Rebbi Yehoshua ben Levi chose the wording "Shishim v'Achas," Tosfos suggests that this implies he meant sixty-one permitted eggs in addition to the forbidden one.

This inference works only if we assume that Rebbi Yehoshua ben Levi had two clear options: either to say "Shishim v'Hi," meaning sixty including the Isur, or to say "Shishim v'Achas," meaning sixty-one besides it. Given that the more precise expression was available, Tosfos initially wanted to read significance into the wording he chose.

However, Tosfos then raises another possibility. Perhaps Rebbi Yehoshua ben Levi himself was uncertain about the exact calculation, and therefore used a neutral expression that does not clearly indicate whether the total includes the forbidden egg or not. In that case, the wording "Shishim v'Achas" would not prove anything definitive.

I hope this helps.

Kol Tuv,

Aharon Steiner