אין קורין בתור' בפחות מי' גדולי' בני חורין ואם התחילו בי' ויצאו מקצתן גומרין:

We do not read from the Torah with less than ten adults who are free [i.e. non-slaves]. And if they began with ten and some of them left, they [continue reading until they] finish.

If each Chumash [i.e. each of the five books of the Torah] was written separately, even if they were each rolled like a Torah scroll, we do not read from it until all five [books] are sewn together. Gloss: And they must be rolled like a Torah scroll. But our Chumashim, even if all five books are [bound] together, we do not make the blessing over it (Mordekhai - end of chapter "Hanizkin" and end of chapter "Hakometz", Teshuvot Ramba"n - siman 187 and 199, Rabbeinu Yerucham - Netiv 2, third volume, Agur - in the name of Shibolei Leket, Mahari"k - shoresh 68, and Kol Bo, Positive Mitzvot, chapter 9 of Laws of a Torah Scroll). And in a place that has a Torah scroll, but there is no prayer leader [who is reading for others] who is an expert in reading using the correct cantillation marks by heart, I saw that some have a custom that the prayer leader reads from the Chumash using the markings [i.e. the vowels and/or cantillation marks], and the one who is called up reads after [the prayer leader] from the valid Torah scroll.

Even in villages that do not a valid Torah scroll, they should not recite the blessing upon [reading from] it.

If an error was found in a Torah scroll during the reading, they should take out another Torah scroll and begin [reading] from the place where the error was found, and complete the [number of] readers [i.e. aliyot] that are over [and above] those that were read [in the Torah] that had an error. And if the error was found in the middle reading, the reader should finish [that] reading in a valid Torah and blesses [the closing blessing] after it, and should not go back to bless [that's recited] before. Gloss: If they already read 3 verses along with [the verse that is in error] and it's possible to stop [where the error was found], they stop there and bless [the closing blessing] afterwards, and [then] they conclude the remaining count [of aliyot] in the other Torah scroll that they take out (Mordekhai - chapter 2 in Tractate Megillah). This - that we take out another [sefer Torah] - is specifically when a complete error is found, but if was only because of missing or extra letters, we don't take out another [sefer Torah], since our Torah scrolls are not so precise so as to say that the other one would be more valid (Agur and Piskei Mahari"a - siman 80 and Ria"z). And Mahari"l ruled that another Torah scroll should not be brought, and Beit Yosef ruled that another Torah scroll must be brought (and therefore, we need the above compromise). In an extenuating circumstance, where the congregation has only the invalid Torah scroll, and there is no one there who is able to fix it, there are those who say that it should be read from it and the blessings should be recited (Kol Bo and Abudarham), and some invalidate [it] (Teshuvat HaRashb"a 487 and 405?, and Maimoni on chapter 10 of Laws of a Torah Scroll). And if one of the chumashim [books of the Torah] is complete, without errors, one may be lenient and read from that specific chumash, even though there are errors in the others (Ra"n)

[In] a synagogue that has only one person who knows how to read [Torah], that person should bless [the opening blessing] and read a few verses and then bless [the closing blessing] after them, then repeat [the process] and bless at the beginning, read a few verses, and bless afterwards. And [the reader] should continue doing so as many times as the number of people called up [for aliyot] for that day.