Footnotes
1.
In the order given here, following the order of Mishneh Torah, P107 is the first of the commandments dealing with tumah and taharah (ritual impurity and purity). In the order of Sefer HaMitzvos, however, P96 is the first of these mitzvos, and there the Rambam gives a general introduction to all these mitzvos.
2.
Num. 19:11ff.
3.
Such as which parts of the body convey tumah, how it is conveyed, etc. See Hilchos Tumas Meis.