(Mishnah) Question: What do we say in a Zimun?

Answer: If there are three people in all, the Mezamen says "Nevarech (let us bless)." If there are [at least] three without him (but less than 10 in all), he says "Barchu (bless)";

If there are 10 in all, he says "Nevarech Elokeinu." If there are 10 without him, he says "Barchu [Elokeinu]";

The same applies if there are 10 or [up to] 10,000. (The next clause contradicts this! The Gemara will resolve this.)

If there are 100 in all, he says "Nevarech Hash-m Elokeinu." If there are 100 without him (but less than 1000), he says "Barchu [Hash-m Elokeinu]";

If there are 1000 in all, he says "Nevarech Hash-m Elokeinu Elokei Yisrael." If there are 1000 people without him, he says "Barchu..."

If there are 10,000, he says, "Nevarech Hash-m Elokeinu Elokei Yisrael Elokei Tzevakos Yoshev ha'Keruvim for the food that we ate."

R. Yosi ha'Glili says, the Berachah is according to the number of people -- "b'Makhelos Barchu Elokim Hash-m mi'Mekor Yisrael."

R. Akiva says, we find in the Beis ha'Keneses that the Berachah does not depend on the number of people. We always say "Barchu Es Hash-m"!

R. Yishmael says, we say "Barchu Es Hash-m ha'Mevorach."

(Gemara): A case occurred in which R. Ze'ira, R. Yakov bar Acha, R. Chiya bar Ba and R. Chanina, the colleague of Rabanan were sitting and eating. R. Yakov bar Acha took the cup and blessed. He said Nevarech; he did not say Barchu.

R. Chiya bar Ba: Why did you not say Barchu?

R. Yakov bar Acha: Was it not taught that we are not meticulous about the matter? Whether he said Nevarech, or he said Barchu, we do not correct him! People who are overly meticulous correct him.

R. Ze'ira was upset that R. Yakov bar Acha called R. Chiya bar Ba 'overly meticulous'.

Shmuel: I do not exclude myself from the group. (I always say Nevarech, lest it seem that I tell them to bless, but I will not bless.)

Question: In Birkas ha'Torah [one who reads from the Torah] says Barchu! (We are not concerned that he excludes himself from the group.)

Answer (R. Avun): Since he says [Barchu Es Hash-m] ha'Mevurach (he himself blesses Hash-m), he does not exclude himself from the group.

R. Aba bar Zamina was serving Ze'ira. He mixed the cup (added water to the wine) for him, and told him 'take [it] and bless';

Ze'ira: Intend that you will drink [the cup that you already have, and] another.

(Beraisa): [If he did not have special intent], the waiter blesses on every cup [for he does not expect to get another], and he does not bless on every slice [of bread].

Ze'ira: Just like I intend to exempt you of your obligation in the Brachah, you should intend to fulfill your obligation through answering Amen. (CHAREDIM)

Support (R. Tanchum bar Yirmeyah - Mishnah): One who was Mis'asek [engaged with a Shofar, but he did not intend for the Mitzvah] was not Yotzei, and one who hears from a Mis'asek was not Yotzei.