[Sidenote: Definition of a cubic number and a cube root. Mark off the places in threes. Find the first digit; treble it and place it under the next but one, and multiply by the digit. Then find the second digit. Multiply the first triplate and the second digit, twice by this digit. Subtract. Examples.] Heere folowith{e} the extraccio{u}n of rotis in cubik{e} nombres; wher-for me most se what is a nombre cubik{e}, and what is his roote, And what is the extraccio{u}n of a rote. A nombre cubik{e} it is, as it is before declared{e}, that cometh{e} of ledyng of any nombre twies in hym-self{e}, other ones in his quadrat. The rote of a nombre cubik{e} is the nombre that is twies had{e} in hy{m}-self{e}, or ones in his quadrat. Wher-thurgh{e} it is open, that eu{er}y nombre quadrat or cubik{e} have the same rote, as it is seid{e} before. And forto draw out the rote of a cubik{e}, It is first to fynd{e} þe nombr{e} p{ro}posed{e} yf it be a cubik{e}; And yf it be not, than thow most make extraccio{u}n of his rote of the most cubik{e} vndre the nombre p{ro}posid{e} his rote found{e}. Therfor p{ro}posed{e} some nombre, whos cubical rote þ{o}u woldest draw out; First thow most compt the figures by fourthes, that is to sey in the place of thousand{es}; And vnder the last thousand{e} place, thow most fynde a digit, the which{e} lad{e} in hym-self cubikly puttith{e} a-way that þat is ou{er} his hede as in respect of hym, other as nygh{e} as thow maist. That done, thow most trebill{e} the digit, and that triplat is to be put vnder the .3. next figure toward{e} the right hond{e}, And the vnder-trebill{e} vnder the trebill{e}; Than me most fynd{e} a digit vndre the next figure bifore the triplat, the which{e} w{i}t{h} his vnder-trebill{e} had into a trebill{e}, aft{er}warde other vnder[trebille][{26}] had in his p{ro}duccio{u}n, putteth{e} a-way all{e} that is ou{er} it in regard{e} of[{27}] [the triplat. Then lade in hymself puttithe away that þat is over his hede as in respect of hym, other as nyghe as thou maist:] That done, thow most trebill{e} the digit ayene, and the triplat is to be sette vnder the next .3. figure as before, And the vnder-trebill{e} vnder the trebill{e}: and than most thow sette forward{e} the first triplat w{i}t{h} his vndre-trebill{e} by .2. differences. And than most thow fynde a digit vnder the next figure before the triplat, the which{e} with{e} his vnder-t{r}iplat had in his triplat afterward{e}, other vnder-treblis lad in p{ro}duct [*Fol. 55b] It sitteth{e} a-way ałł that is ou{er} his hede in respect of the triplat than had in hym-self cubikly,[{28}] [[it setteth{e} a-way all{e} his respect]] or as nygh{e} as ye may.