[*119a] Nowe to trye whether that su{ m}me be well added or no, I wyll subtract one of the fyrst two su{ m}mes from the thyrd, and yf I haue well done y^e remayner wyll be lyke that other su{ m}me. As for example: I wyll subtracte the fyrste summe from the thyrde, whiche I set thus in theyr order.
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Then do I subtract 2000 of the fyrste summe fro{ m} y^e second su{ m}me, and then remayneth there 5000 thus.
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Then in the thyrd lyne, I subtract y^e 100 of the fyrste summe, fro{ m} the second su{ m}me, where is onely 100 also, and then in y^e thyrde lyne resteth nothyng. Then in the second lyne with his space ouer hym, I fynde 80, which I shuld subtract [*119b] from the other su{ m}me, then seyng there are but only 70 I must take it out of some hygher summe, which is here only 5000, therfore I take vp 5000, and seyng that it is to moch by 4920, I sette downe so many in the seconde roume, whiche with the 70 beynge there all redy do make 4990, & then the summes doth stande thus.
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Yet remayneth there in the fyrst su{ m}me 9, to be bated from the second summe, where in that place of vnities dothe appere only 7, then I muste bate a hygher su{ m}me, that is to saye 10, but seynge that 10 is more then 9 (which I shulde abate) by 1, therfore shall I take vp one counter from the seconde lyne, { and} set downe the same in the fyrst [*120a] or lowest lyne, as you se here.
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And so haue I ended this worke, { and} the su{ m}me appereth to be y^e same, whiche was y^e seconde summe of my addition, and therfore I perceaue, I haue wel done.
_M._ To stande longer about this, it is but folye: excepte that this you maye also vnderstande, that many do begynne to subtracte with counters, not at the hyghest su{ m}me, as I haue taught you, but at the nethermoste, as they do vse to adde: and when the summe to be abatyd, in any lyne appeareth greater then the other, then do they borowe one of the next hygher roume, as for example: yf they shuld abate 1846 from 2378, they set y^e summes thus.