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https://newatlas.com/science/decimal-point-history-older/
Historians have discovered what may be the world's first decimal point, in an ancient manuscript written 150 years before its next known appearance. There have been many ways to split integers, but this little dot has proven uniquely powerful.
The mathematics we all learn at school seems so fundamental that it doesn't feel like individual concepts in it would need "inventing," but these pieces arose separately as scientists and mathematicians realized they were needed. For instance, scientists recently found the oldest written record of the numeral "0," dating back 500 years earlier than previously thought.
Now, it looks like the decimal point is also older than expected. Ever since we've realized we sometimes need to break numbers into smaller fragments, humans have denoted the difference using various symbols – dashes, vertical lines, arcs and underscores have filled the role, but none of those have survived into modern usage. Commas and periods are the most common now, so when did they start?
Previously, the earliest known use of a period as a decimal point was thought to be an astronomical table by the German mathematician Christopher Clavius in 1593. But according to modern scientists, that kind of test is a weird place to introduce such a massive concept to the world, and Clavius didn't really go on to use the idea much in his later writings. Basically, if he realized the need for the concept and invented a neat way to display and work with it, why didn't he brag about it?
The answer, it seems, is that Clavius was just borrowing an older idea that had essentially been lost to time, and wasn't the preferred method in his era. A new study has found that the decimal point dates back to the 1440s – about 150 years earlier – first appearing in the writings of Italian mathematician Giovanni Bianchini.
Bianchini was a professor of mathematics and astronomy at the University of Ferrara, but he also had a background in what we'd now call finance – he was a merchant, and managed assets and investments for a wealthy ruling family of the time. That real-world experience seems to have influenced his mathematical work, since Bianchini was known to have created his own system of dividing measurement units like feet into 10 equal parts to make them easier to work with. As fundamental as it feels to modern sensibilities, it didn't catch on with the 15th century crowd who were used to a base-60 system.
Now, Dr. Glen Van Brummelen, a professor at Trinity Western University in Canada, has discovered that Bianchini illustrated this system with a decimal point, the first ever. Van Brummelen found that in a manuscript called Tabulae primi mobilis B, Bianchini was using numbers with dots in the middle – the first one being 10.4 – and showing how to multiply them, something that was tricky in a base-60 system.
"I realized that he's using this just as we do, and he knows how to do calculations with it," Van Brummelen told Nature. "I remember running up and down the hallways of the dorm with my computer trying to find anybody who was awake, shouting 'look at this, this guy is doing decimal points in the 1440s!'"
Journal Reference:
Glen Van Brummelen, Decimal fractional numeration and the decimal point in 15th-century Italy, Historica Mathematica, In Press, 2024. https://doi.org/10.1016/j.hm.2024.01.001
(Score: 3, Insightful) by pTamok on Monday February 26 2024, @09:37AM
There are several inventions/techniques, found independently, that contributed towards the contemporary methods of arithmetic ( which is a part of mathematics ).
1) Positional notation
2) Using base-10
3) Using an explicit symbol to denote 'zero' (and, indeed, separate unique, individual symbols for each number, so '3' is '3' and not, for example, 'Ⅲ', or Babylonian numerals [st-andrews.ac.uk])
4) Using a symbol to divide non-fractional and fractional parts of a number (or the division between the positional notation fields of base0 and base-1)
5) Cheap paper (or equivalent)
This is not to say one cannot do arithmetic without any or all of them: obviously, one can - in the past, sand-tables, counting-boards, wax-tablets and abaci were used. It would be a waste of vellum to use it for scratch calculations.
I think the interesting thing here is not that someone discovered the utility of using a standardised divider between the fractional and non-fractional parts of a number, but how long it took to be generally adopted. I would hazard a guess that at the time Giovanni Bianchini starting using the technique, most people could not read or write, and dissemination of novel knowledge between people who could read and write was remarkably slow, partly down to the need to hand-copy books - we are talking the 1440s here, and moveable-type printing was just taking off in Europe.