Counting Number Angles
Date: 10/13/2002 at 13:25:53 From: Terri R Subject: Counting Number Angles I am trying to find the history of counting number angles. I was told by my professor that the way the numbers were written gave you the number in the number of angles in the written number, such as the number 2 being written as what we know as a Z: there are two angles in this number, meaning it is the number 2. Can you give me more information on this type of math history?
Date: 10/13/2002 at 23:42:35 From: Doctor Peterson Subject: Re: Counting Number Angles Hi, Terri. In Cajori's _A History of Mathematical Notations_ (p. 65), there is a chart showing "Fanciful hypotheses on the origin of the numeral forms." One of these (II) suggests that the numerals originated as various numbers of dots, which were connected with lines; another (V) shows various numbers of angles as you describe: __ __ _ _ _ __ _ /| / / \/ |_ |_ ' / \/ |_|_ | /_ _\ /\ ,_| |_| _|_ /\ ,_| | Cajori says, "A French writer, P. Voizot, entertained the theory that originally a numeral contained as many angles as it represents units, as seen in Part V. He did not claim credit for this explanation, but ascribed it to a writer in the Genova Catholico Militarite. But Voizot did originate a theory of his own, based on the number of strokes, as shown in Part VI." __ __ __ __ __ __ | | | | | |__ |__ |__| /\ /\ | | __| |__| __| |__| |__| \/ \/ /\ /\ \/ \/ / These are all entirely imaginary explanations of the origin of the symbols. It is not math history. To read about how they really originated, see the article at the MacTutor History of Mathematics archive at St. Andrews University: The Arabic numeral system http://www-history.mcs.st-and.ac.uk/HistTopics/Arabic_numerals.html If you have any further questions, feel free to write back. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/
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