Mishnayos Demai Perek 5 Mishnah 1

הלוקח מן הנחתום – when the baker [who does not observe certain religious customs regarding tithing] sells [loaves of bread] in large measures (i.e., bulk), a person who purchases from him is obligated to make things legally fit for use by giving the priestly dues, and the baker is exempt [from tithing]. But surely, in that it is taught in the Mishnah above in chapter 2 (in Mishnah 4) that bakers are obligated to separate so that there is a measure for a limit for the heave-offering of tithe [which is given to the Levite] and Hallah [given to a Kohen, usually one forty-eighth for a commercial baker as opposed one twenty-fourth for a private person]. There (i.e., in Tractate Hallah, Chapter 2, Mishnah 4) it is speaking about a person who sells in small quantities (i.e., retail) because he profits greatly, they {i.e., the Rabbis) placed upon him [the responsibility] to tithe; alternatively, because the young children that purchase from someone [who sells] in small portions (i.e., retail), in order that they will not consume eatables forbidden pending the separation of sacred gifts, they (i.e., the Rabbis) placed upon him [the obligation] to make things legally fit for use by giving the priestly dues. The terms מדה גסה/large quantities and דקה/small quantities is explained at the end of the second chapter [of Tractate Demai, Mishnah 5].

נואל כדי תרומת מעשר – which is one [part] in one-hundred (i.e, 1/100) and so he can give Hallah [to the Kohen] one in forty-eight [parts] (i.e., 1/48). But he should not separate them from the loaf that he purchased from the baker, but rather established for them a place and leaves them attached in their place.

אחד ממאה ממה שיש כן – from everything that is here, implying, even with according to the quantity of Hallah that he separated is made into a tithe, and it is found that he separates the tithe (i.e., First Tithe) even from the Hallah portion.

ושאר מעשר – that is another nine [parts] that are next to it, he established a place for the entire [First] Tithe, and that one that one-part that I called it by the name of “[First] Tithe} at first is made into the heave-offering of the tithe (i.e., that which the Levite gives to the Kohen) on the nine [parts] that are near it.

והשאר חלה – one out of forty-eight [parts] (i.e., 1/48) that I separated out as Hallah [for the Kohen].

ומעשר שני בצפונו או בדרומו – he establishes for himself a place and afterwards he redeems it, but he does not need to add the [additional] one-fifth.