Timeline for Were decimal fractions known in Europe before Stevin?
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| Oct 27, 2019 at 7:44 | comment | added | Conifold | @Chrystomath There was a trick for roots, where the number was multiplied by an even power of 10 and then the answer divided by 10 to half that power, to avoid fractions. It was known in Europe as early as Hispalensis (c.1140), and Ries included it into his Rechnung (1522), see Smith, p.236. You'll have to inspect della Porta's writing closer to see if he had algorithms for calculations on fractions or simply used the trick and wrote answers with a point. | |
| Oct 27, 2019 at 6:40 | comment | added | Chrystomath | I also thought at first that della Porta's use was purely notational. But actually it is the result of a calculation of a square root, as in the root of 172800 is 415.6.9. Since della Porta wasn't a mathematician as such, perhaps Italians were already using decimal fractions in 1558? | |
| Oct 26, 2019 at 22:57 | history | edited | Conifold | CC BY-SA 4.0 |
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| Oct 26, 2019 at 22:42 | history | answered | Conifold | CC BY-SA 4.0 |