¶ Her{ e} he putt{ es} þe Thryd case, þe quych is þis, yf of duplacio[n~] of a fig{ ur}e come a Composit. þ{ o}u schalt do away þe fig{ u}re þ{ a}t is doublet & set þ{ ere} a digit of þe Composit, & sett þe articull{ e} ou{ er} þe next figures hede, & aft{ er} draw hym downe w{ i}t{ h} þe figur{ e} ou{ er} whos hede he stondes, & make þ{ ere}-of an nombre as þ{ o}u hast done afore, & yf þ{ ere} come no fig{ ur}e aft{ er} þat digit þat þ{ o}u hast y-write, þa{ n} set þe articull{ e} next aft{ er} hym in þe same rewe as þus, 67: double 6 þat wel be 12, do away 6 & write þ{ ere} þe digit [*leaf 148a] of 12, þe quych is 2, and set þe articull{ e} next aft{ er} toward þe lyft side in þe same rewe, for þ{ ere} comes no figur{ e} aft{ er}. þan dowble þat oþ{ er} figur{ e}, þe quych is 7, þat wel be 14. the quych is a Composit. þen do away 7 þat þ{ o}u doublet & sett þe þe diget of hy{ m}, the quych is 4, sett þe articull{ e} ou{ er} þe next figur{ es} hed, þe quych is 2, & þen draw to hym þat on, & make on nombre þe quych schall{ e} be 3. And þen yf þ{ o}u haue wel y-do þ{ o}u schall{ e} haue þis nombre of þe duplacio[n~], 134. v{ er}sus.
¶ Si super ext{ re}ma{ m} nota sit monade{ m} dat eid{ em} Quod t{ ibi} { con}tingat si p{ ri}mo dimidiabis.
[Sidenote: How to double the mark for one-half. This can only stand over the first figure.]
¶ Her{ e} he says, yf ou{ er} þe fyrst fig{ ur}e in þe ry[gh]t side be such a merke as is her{ e} made, ^w, þ{ o}u schall{ e} fyrst doubull{ e} þe figur{ e}, the quych stondes vnd{ er} þ{ a}t merke, & þen þou schalt doubul þat merke þe quych stond{ es} for haluendel on. for too haluedels makes on, & so þ{ a}t wol be on. cast þ{ a}t on to þat duplacio[n~] of þe figur{ e} ou{ er} whos hed stode þat merke, & write it in þe same place þ{ ere} þat þe figur{ e} þe quych was doublet stode, as þus 23^w. double 3, þat wol be 6; doubul þat halue on, & þat wol be on. cast on to 6, þ{ a}t wel be 7. do away 6 & þat 1, & sett þ{ ere} 7. þan hase þou do. as for þat figur{ e}, þan go [*leaf 148b] to þe oþ{ er} fig{ ure} & worch forth. & þ{ o}u schall neu{ er} haue such a merk but ou{ er} þe hed of þe furst figure in þe ryght side. And [gh]et it schal not happe but yf it were y-halued a-for{ e}, þus þ{ o}u schalt vnd{ er}stonde þe verse. ¶ Si sup{ er} ext{ re}ma{ m} &c. Et nota, talis fig{ ur}a ^w significans medietate{ m}, unitat{ is} veniat, { i.e.} contingat u{ e}l fiat sup{ er} ext{ re}ma{ m}, { i.e.} sup{ er} p{ ri}ma{ m} figura{ m} in ext{ re}mo sic v{ er}sus dextram ars dat: { i.e.} reddit monade{ m}. { i.e.} vnitate{ m} eide{ m}. { i.e.} eidem note & declina{ tur} hec monos, d{ i}s, di, dem, &c. ¶ Quod { er}g{ o} to{ tum} ho{ c} dabis monade{ m} note { con}ting{ et}. { i.e.} eveniet tibi si dimidiasti, { i.e.} accipisti u{ e}l subtulisti medietatem alicuius unius, in cuius principio sint figura nu{ mer}u{ m} denotans i{ m}pare{ m} p{ rim}o { i.e.} principiis.