[4.] These figures are removed at the next step.
[5.] Slates are mentioned by Chaucer, and soon after (1410) Prosdocimo de Beldamandi speaks of the use of a “lapis” for making notes on by calculators.
Egerton 2622.
HEc algorismus ars presens dicitur; in qua
Talibus indorum fruimur bis quinque figuris.
A derivation of Algorism. This boke is called þe boke of [algorym], or Augrym after [lewder] vse. And þis boke tretys þe [Craft] of Nombryng, þe quych crafte is called also Algorym. Ther was a kyng of Inde, þe quich [heyth] Algor, & he made þis craft. And after his name he called hit algorym; Another derivation of the word. or els anoþer cause is quy it is called Algorym, for þe latyn word of hit [s.] Algorismus comes of Algos, grece, quid est ars, latine, craft oɳ englis, and rides, quid est numerus, latine, A nombur oɳ englys, inde dicitur Algorismus per addicionem huius sillabe mus & subtraccionem d & e, quasi ars numerandi. ¶ fforthermore ȝe [most] vndirstonde þat in þis craft ben vsid teen figurys, as here bene writen for ensampul, φ 9 8 7 6 5 4 3 2 1. ¶ [Expone] þe too versus afore: this present craft ys called Algorismus, in þe quych we vse teen signys of Inde. Questio. ¶ Why teɳ fyguris of Inde? Solucio. for as I haue sayd afore þai were fonde fyrst in Inde of a kynge of þat Cuntre, þat was called Algor.