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Roman Mathematics


M. Porcius Cato

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Re compounding periods. On a two year loan, the compunding period may be annual, semi-annual or monthly, etc. Think of a 0% bond. It is the compounding periods that are critical in determining the sum returned.

 

Yes, of course. But if we vary the compounding period over an infinite hypothetical space, is there any value which returns an algorithm for calculating financial losses on one's fingers?

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Yes, of course. But if we vary the compounding period over an infinite hypothetical space, is there any value which returns an algorithm for calculating financial losses on one's fingers?

 

This entire statement is beyond my 'cognitive methods'.

Edited by Gaius Octavius
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Phew - gents! Well, all I know is that Atticus' fingers must have been a lot better than mine. :whistling:/>/>

 

But more seriously, did Cicero mean to imply that Atticus would count on his fingers, or was he referring to Atticus' speedy fingers on an abacus? Just a thought that struck me.

 

You may find a previous thread also titled "Roman Mathematics" currently at the bottom of page 3 of Romana Humanitas can provide some guidance on Roman interest calculations and the use of 'finger' and abacuses (I am informed that abacus is not a Roman word and so the plural is NOT 'abacii'). My post of August 14 2006 at 02:19Am in that thread and some of the following posts describe the use of a Roman Pocket Calculator (which was a form of abacus but streamlined for portability). It includes the following link to the site of Prof. Dr. J

Edited by Ruthe
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It is not hard to see why the Romans set their standard rate of interest at 12% and its multiples and factors given their use of duodecimal fractions.

 

But they were also known to charge interest at rates other than 12% and its multiples and factors. We have Latin terms for:

 

Asses usurae, or one as per month for the use of one hundred = 12 per cent

Deunces usurae 11 per cent

Dextantes usurae 10 per cent

Dodrantes usurae 9 per cent

Besses usurae 8 per cent

Septunces usurae 7 per cent

Semisses usurae 6 per cent

Quincunces usurae 5 per cent

Trientes usurae 4 per cent

Quadrantes usurae 3 per cent

Sextantes usurae 2 per cent

Unciae usurae 1 per cent

Edited by M. Porcius Cato
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It is not hard to see why the Romans set their standard rate of interest at 12% and its multiples and factors given their use of duodecimal fractions.

 

But they were also known to charge interest at rates other than 12% and its multiples and factors. We have Latin terms for:

 

Asses usurae, or one as per month for the use of one hundred = 12 per cent

Deunces usurae 11 per cent

Dextantes usurae 10 per cent

Dodrantes usurae 9 per cent

Besses usurae 8 per cent

Septunces usurae 7 per cent

Semisses usurae 6 per cent

Quincunces usurae 5 per cent

Trientes usurae 4 per cent

Quadrantes usurae 3 per cent

Sextantes usurae 2 per cent

Unciae usurae 1 per cent

 

I did not imply that other rates were not used, only that the standard was 12%. As for all the other rates, these were all elements of the duodecimal fractions used by the Romans. The first group below were used for both weights and lengths and a subset were used for fractional parts of capacities but with different names.

............................As=1........Uncia=1

As......................12/12.............12

Deunx................11/12.............11

Dextans..............10/12..(5/6)...10

Dodrans................9/12.(3/4).....9

Bes.......................8/12.(2/3).....8

Septunx.................7/12.............7

Semis....................6/12.(.1/2)....6

Quincunx...............5/12..............5

Triens....................4/12.(1/3).....4

Quadrans...............3/12.(1/4).....3

Sextans.................2/12.(1/6).....2

Sesuncia................1/8............1 1/2

Uncia.....................1/12.............1

 

In addition, there were also the following fractions.

 

Semuncia].............1/24............1/2

Duella]...................1/36...........1/3

Sicilicus]................1/48............1/4

Sextula]................1/72............1/6

Drachma]..............1/96............1/8

Dimidio sextula]....1/144...........1/12

Tremissis]............1/216...........1/18

Scrupulus]............1/288...........1/24

Obulus]................1/576...........1/48

Bissiliqua]............1/864...........1/72

Cerates]..............1/1152..........1/96

Siliqua]................1/1728..........1/144

Calcus]................1/2304..........1/192

 

What I intended was to illustrate the Roman use of duodecimal fractions as part of the argument that they were far more capable practical mathematicians then previously portrayed. Simply because of their unusual and unwieldy written numeral system, it has been implied that they were incapable of performing complex calculations. This is an argument to refute that impression.

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