The Barddas of Iolo Morganwg, Vol. I., ed. by J. Williams Ab Ithel, , at sacred-texts.com
p. 108 p. 109
Here is the system of numerals, that is, the particulars of the art of Arithmetic, (from the Book of D. Richard, Llandochen.) They are removed from point to point according to this method, that is, every one of the points being itself a number, on whatever point it may be, will make the next to be above it. These are the names of the points:--One, ten, hundred, thousand, myriad, million, mwnt, rhiallu, buna, tyrva, catyrva, cadrawd.
That is, ten ones are ten, ten tens are a hundred, ten hundreds are a thousand, ten hundred thousands are a myriad, a myriad myriads are a million, a million millions are a mwnt, 1 a mwnt mwnts are a rhiallu, a rhiallu rhiallus are a buna, a buna bunas are a tyrva, 2 a tyrva tyrvas are a cattyrva, a cattyrva cattyrvas are a cadrawd, 3 a cadrawd cadrawds are the number of lives from Annwn to Gwynvyd, &c. (Llywelyn Sion.)
109:1 p. 109 "Mwnt" is probably of cognate origin with a mons, mount, mynydd.
109:2 Tyrva, Lat. turba, a multitude, a crowd.
109:3 Cadrawd, (cad-rhawd,) the rage or course of battle; an army.