Answer: One of them is needed for context (and is not expounded). One teaches about the Sechach, and three teach about walls;

A tradition from Moshe from Sinai teaches that one of the three walls can be as small as a Tefach (and a drop, if it is positioned properly).

Question: It says that a Yoledes Nekevah will be Teme'ah "Shevu'ayim (two weeks)." Beis Hillel should expound also the Mesores (without a 'Vov', suggesting 'Shiv'im (70)'), and we should take the average of these, 42 days!

Answer: It says "k'Nidasah." (Rashi - it is close to the seven days of Nidah, therefore we do not expound that way; Tosfos - her Tum'ah is like the (seven) days of Nidah more than the (seven) days of Yoledes Zachar.)

(Beraisa) It says "v'Chiper" three times, lest we err about Zerikah. (It says v'Chiper regarding a male goat (of a Nasi), a female goat, and a female lamb. These are outer Chata'os, i.e. their blood is put on the outer Mizbe'ach.)

Suggestion: We should learn the law of upper blood (that is put on top of the Mizbe'ach, i.e. of a Chatas) from lower blood (put on the bottom of the Mizbe'ach, i.e. other Korbanos). Just like one Zerikah of lower blood is Mechaper, also one Zerikah of upper blood!

Counter-suggestion: Perhaps we should learn outer Chata'os) from inner Chata'os (of Yom Kipur or Par He'elem Davar (a bull to atone for a mistaken ruling of the Great Sanhedrin that caused most of Yisrael to transgress an Isur Kares), whose blood is put on the inner Mizbe'ach). Just like every Zerikah of inner Chata'os is Me'akev, also of outer Chata'os!

Decision: We should learn from whichever is more similar.

Suggestion: We should learn outer Korbanos from outer Korbanos, and not from inner Korbanos.

Counter-suggestion: We should learn Chata'os that require (Zerikah on the) four Keranos from Chata'os that require four Keranos, and not from other Korbanos!

Resolution: Since we would not know from which to learn, it says "V'Chiper" three times:

"V'Chiper" - even if only three Zerikos were done (it is Mechaper); "v'Chiper" - even if only two Zerikos were done; "v'Chiper" - even one Zerikah is Mechaper.

Question: Each "v'Chiper" teaches that this kind of Chatas is Mechaper. (None is extra.)

Answer (Rava citing Bar Ada Mari) Question: Each time it says "v'Chiper", it says also "v'Nislach". Kaparah is Selichah (forgiveness)!

Answer: Each "v'Chiper" is extra to teach that one of the Zerikos is not Me'akev.

Question: Perhaps we should expound a smaller Chidush! "V'Chiper" - even if three Zerikos were done above and one below; "v'Chiper" - even two Zerikos were above and two below; "v'Chiper" - even if the Zerikos were only below! (Tosfos - it is more reasonable to be Machshir when the Zerikos below are in a way that the Torah proscribed for lower Zerikos, e.g. on two corners that encompass all four sides, than when three Zerikos are below; Rashi (according to Tosfos) - if it is Mechaper even when most of the Zerikos are below, surely it is Mechaper even if all the Zerikos are below.)

Answer #1: (Rav Ada bar Yitzchak): If so, putting on the Keranos above would not be Me'akev!

Rejection: If the Torah teaches that they are not Me'akev, indeed, they are not Me'akev!

Answer #2 (Rava): It says "v'Chiper" only three times, so we cannot expound to Machshir all four Zerikos below. (He holds that it is more reasonable to be Machshir three Zerikos below than four, unlike the one who asked Question (d).)

Question: We should expound "v'Chiper" - even if three Zerikos were done above and one below; "v'Chiper" - even if two were above and two below; "v'Chiper" - even if three were below and one above!

Answer: We never find that some of the blood is thrown on top and some on bottom.

Question: We do find this!

Question #1 (Mishnah): He threw (the blood of an inner Chatas) once above and seven times below.

Answer: He was Matzlif (flicked his hand), i.e. all the blood went to the same place. 'Above' and 'below' refers to the position of his hand.

Question #2 (Mishnah): He sprinkled seven times on Tiharo of the inner Mizbe'ach.

Suggestion: Tiharo means the middle. (Rashi - surely, some of the blood will go above and some below; Tosfos - other Zerikos are put on top.) This is why noon is called Tiharah!

Answer (Rabah bar Shila): No, it means the top - "uch'Etzem ha'Shamayim la'Tohar."

Question: The Shirayim are put on the bottom!

Answer: They are not Me'akev. (We never find that blood that is Me'akev is put partially on top and partially on bottom.)

Question: There is an opinion that Shirayim of inner Chata'os are Me'akev!

Answer: We never find that blood that is Me'akev is put partially on top and partially on bottom of the same Mizbe'ach.

(Beraisa - R. Eliezer ben Yakov): Beis Shamai say that two Zerikos for an (outer) Chatas, or one Zerikah for other (outer) Korbanos, permit (offering the Eimurim and eating the meat) and determine (whether or not the Korban is) Pigul;

Beis Hillel say that one Zerikah for any (outer) Korban permits and determines Pigul.

Question (R. Oshaya): If so, this should be listed (in Maseches Eduyos) among the places where Beis Shamai is more lenient than Beis Hillel! (The wording of the Mishnah implies that Beis Shamai say that one is Mefagel in Zerikah only if both Zerikos were with intent Chutz li'Zmano.)

Answer (Rava): This was taught in response to the question 'how many Zerikos are needed to Machshir the Korban?' Regarding this, Beis Shamai are more stringent.

(R. Yochanan): The (last) three Matanos (Zerikos) of a Chatas may not be done at night, but they may be done after the owner died. One who offers them outside (the Mikdash) is liable;

(Rav Papa): In some respects, they are like the first Zerikah (which is Mechaper). In some respects, they are like the Shirayim (which are not Mechaper);

Regarding the following, they are like the first Zerikah.

Intent (Chutz) in these Matanos disqualifies; one may not do them at night, or by a Zar; one must use a Keli Shares; one must put them on the Keren, using the finger; (if the blood splashed on a garment,) it must be washed (in the Azarah); the remaining blood is put on the Yesod.

Regarding the following, they are like the final law of the blood (Shirayim);

They may be done after the owner died; they do not permit anything; intent of Chutz li'Zmano is not Mefagel; they do not (disqualify the Korban if they) enter the Heichal.

Support (Rav Papa for himself - Mishnah): If blood splashed from the Korban's neck onto a garment, it need not be washed;

If blood splashed from the Keren or the Yesod onto a garment, it need not be washed.

Inference: If blood Ra'uy for (that should have been put on) the Keren splashed onto a garment, it must be washed!

Objection: If so, we should also infer that if blood Ra'uy for the Yesod splashed onto a garment, it must be washed, but this is wrong!

(Beraisa): "Asher Yizah" excludes (from the obligation to wash a garment that absorbed) blood of a Korban after Zerikah.

Version #1 (Rashi): The Mishnah is like R. Nechemyah (he obligates washing even Shirayim, but Chachamim exempt washing even blood of the three Matanos).

Version #2 (Tosfos) Answer #1: The Mishnah is like R. Nechemyah. (He obligates washing blood for which one is liable (for offering it) outside. Likewise, since one is liable for the last three Matanos outside, such blood must be washed.) (end of Version #2)

(Mishnah - R. Nechemyah): If one offered Shirayim outside, he is liable.

Question (Tosfos - against Rav Papa; Rashi - this challenges Objection (d), it is Answer #1 for Rav Papa): Indeed, R. Nechemyah is Mechayev for Shirayim outside, just like one is liable for offering Eimurim outside. We cannot prove that he requires washing!