The leader should include himself in the zimun blessing and say נברך instead of ברכו.

Better to say בטובו than מטובו , bc the mem limits they amount of good from Hashem.

In most requests we limit how much we ask HaShem but for Torah we ask in limitless bounds.

We say שאכלנו בשלו and not למי שאכלנו to recognize that it is only HaShem we are thanking.

We must be careful not to say על המזון שאכלנו so it’s doesn’t appear like we’re thanking the food itself, but this is only with a zimun of 3, but not with 10, where we clearly mention Hashems name.

It’s a dispute between r akiva and r Yosi if we increase name of HaShem if the group is larger or if we always keep the same נוסח once it reaches 10.

The Gemara relates a practice of people eating with the reish gelusa that they weren’t able to hear the zimun well bc of the large crowd so they would quietly make zimun of 3 without the reish gelusa noticing.

3, 4, or 5 people who ate together cannot break up bc of the obligation of zimun on them. However, 6 may break up into 2 groups of 3. 10 may not break up, but 20 may break up to two groups of 10.

Two groups that ate in close enough proximity that some of each group could see the other group can be considered one group for zimun.

Obligation to make zimun sets in as soon as people sit down to eat with each other, even before they’ve eaten. So one person can’t break off from group of 3 from that point and on.

3 people from 3 Seperate groups that each were obligated in zimun can combine together for zimun when they actually bentch.

A common waiter can combine two groups for zimun even if they can’t see each other.

Concentrated wine without water dilution is a dispute. R eliezer says it is not considered drinkable and it’s therefore not hagafen and one can wash netilas yadayim with it. The rabanan consider it drinkable bc it can be mixed with other drinks and it is therefore hagafen and one can’t use it from netilas yadayim. (Everyone agrees by cup of bracha the wine should be diluted first)

One shouldn’t ruin bread by placing raw meat on it. One shouldn’t throw bread or pass a cup of wine that would spill over bread. For other foods, it depends if the food will get ruined. For example, one can throw hard nuts but not soft figs that will be ruined.