ט' ציבורין של מצה וא' של חמץ ובא עכבר ונטל ולא ידענו אם נטל חמץ או אם נטל מצה ונכנס לבית בדוק צריך לחזור ולבדקו (מיהו אם הככר קטן שיכול העכבר לאכול תלינן להקל שאכלו וא"צ לבדוק (טור) שכל הקבוע כמחצה על מחצה ואם פירש הככר ממקום קביעתו ונטלו העכבר משם א"צ לחזור ולבדוק דכל דפריש מרובא פריש:

Nine piles of matza, and one of chametz, and a mouse comes and takes [from the piles] and we do not know if the mouse took chametz or matza, and the mouse entered a checked house - you must return and check it (however, if the food is small enough that the mouse could have eaten it - we can rely on a leniency that the mouse did eat it, and you do not need to check) (Tur), as every established place is like a half of a half [i.e. each established location is treated as its own majority]. If the food was separated from its established place, and the mouse took it from there - you do not need to return and check it, as anything separated [is considered to be] separated from the majority.

If there are two piles, one of chametz and one of matzah, and two houses, one that was checked and one that was not, and two mice came — one took chametz, and one took matzah — and we do not know which mouse entered which house: Or if both houses were checked and there was one pile of chametz, and a mouse came and took from it, and it is not known into which house it entered; Or even if we know it entered one of them, and someone entered after it and checked and found nothing, Or he checked part of the house and found a loaf, In all these cases, there is no need to recheck the house. (These are the words of the Rambam, but the conclusion of later halakhic authorities is not in agreement with him.)

If one left nine loaves of chametz and found ten, he must check for all nine, because we say that what he left was taken, and these are others (i.e., new ones). Similarly, if he left ten and found nine, he must check for all ten. But some say this only applies when the loaves were tied together, but if they were not tied, he only needs to check for the one that is missing or added.

If he left chametz in one corner and found it in another corner, he must recheck the house.