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Monday, November 14, 2011

The Abacus and its Development


By:  Joe Hruban
A Russian Abacus at the Ashmolean Museum, Oxford

            The Abacus was an advantageous tool to use to count numbers and do simple operations.  It helped count, add, subtract, and a little bit of multiplication and division.  It assisted the user in calculations and was used by many different cultures.  This gave it many different forms as well.  However, the history of its development begins in Sumer.

The Abacus first originated in Ancient Sumer sometime in the mid 2000s B.C.  It is possible that the Babylonians used it to make calculations, however it is not for certain.  We start to gain a little more certainty of the abacus when we get to Egypt.  The Greeks mentioned that Egyptian used counters or pebbles to help with calculations or just counting.  The Persians begin to use the abacus after this, yet, it isn’t until the Geeks that we actually have proof that the abacus was used.  With the Greeks, tables with some sort of counters in them have been discovered.  The Romans adopt this from the Greeks.  The Chinese and Russians also used the abacus and made further changes to it.  W. W. Rouse Ball (1912) states that “this instrument was in use among nations so widely separated as the Etruscans, Greeks, Egyptians, Hindoos, Chinese, and Mexicans,” to show the popularity and vast spread of this instrument.  This expansive distribution of the abacus leads to its development and modifications.

The abacus went through many changes and modifications as it progressed from place to place.  It first started out as a wooden board with grooves cut into it.  These grooves were made to hold pebbles or counters of some kind.  A variation of this form was a table covered with sand with grooves in it that were made by someone’s fingers.  However, it was the same concept.  To represent a number, one would look at the grooves and the pebbles to understand place and value, respectively.  The number of pebbles or counters in the first groove signified the value of the one’s place.  The number of pebbles in the second groove represented the value of the ten’s place, and so on.  Once you reach ten in any of the grooves, you clear that groove and put one pebble in the following groove.  One must keep in mind that whichever groove was considered the first groove depended on which way the culture that was using it read; in other words, left to right or right to left.  This model of the abacus was just the template for another form, the swan-pan.

The swan-pan was a form of the abacus where there were parallel wires within a wooden frame.  This is the form that we know today when we think of an abacus.  The swan-pan of the Greeks and Romans did not have a top to the frame.  This was so they could place or remove their counters on the wires.   They created two margins on their abaci: one with four counters and one with twelve counters.  This signified the addition of fractions with denominators of four or twelve.  Their abaci were made to represent numbers of up to one-hundred million.  Although this abacus suited the needs of the Greeks and Romans, the Russians decided to modify it further. 

The Russians made some changes to the abacus as well to suit their needs.  They elongated the wires and put nine or ten beads on each wire and closed the frame.  This eliminated the need to add or remove beads from each wire and since the wires were longer, all they had to do was slide the desired beads up or down to represent the number they needed.  Gerbert added to this by coloring the beads different colors and by marking them one through nine.  This made using the instrument more organized and slightly quicker.  The Chinese saw further developments that could be made.

The Chinese and Japanese made a slightly different model.  There model had a top row with two beads on each wire and a bottom row with five beads on each wire.  To represent a number, one would slide the beads up towards the divider.  The two beads above the divider represent a value of five (in decimal notation) so if one would want to represent the number seven, the beads in the top row would be one up and one down and the beads in the bottom row would be two up and three down.  This made performing the operations of addition, subtraction, multiplication, and division, much faster.  Ball (1912) stated “I am told that an expert Japanese can, by the aid of a swan-pan, add numbers as rapidly as they can be read out to him.”  The abacus was a great aid to the Japanese as well as many other civilizations.

The abacus helped civilizations in making calculations until the invention of the conventional calculator.  It went through many changes with each civilization that used it but benefitted all.  The fact that the idea of it stayed relatively concrete throughout every civilization it was a part of further solidifies its notion of an effective tool.   

Bibliography
Ball, W. W. R. (1912). A Short Account of The History of Mathematics. London, England: Macmillan & Co., Ltd. 123-126.      

Friday, November 11, 2011

Happy 11/11/11


Happy 11/11/11!! Here are a few interesting facts related to such numbers!

11×11 = 121
111×111 = 12321
1111×1111 = 1234321
11111×11111=123454321
111111×111111=12345654321
....

1 / 11 = 0.09 09 …
2 / 11 = 0.18 18 …
3 / 11 = 0.27 27 …
4 / 11 = 0.36 36 …
5 / 11 = 0.45 45 …
6 / 11 = 0.54 54 …
7 / 11 = 0.63 63 ...
....

11-3×3=2
1111-33×33=22
111111-333×333=222
11111111-3333×3333=2222
....

Monday, April 4, 2011

Timothy Gowers Speaks at CMI (year 2000)

Timothy Gowers received the Fields Medal for research on functional analysis and combinatorics in 1998. In the year 2000, he was the Keynote Speaker at the Clay Mathematics Institute where he spoke about various applications of mathematics in other areas such as computer science, finance and engineering. His speech is remarkably clear and easy to follow. You can watch his speech here..


 

Saturday, November 6, 2010

History of Math Contest

The Mathematical Association of America has its eighth annual undergraduate student writing contest in the History of Mathematics. This contest is open to all undergraduate students. Deadline for submission is March 31st. More information (including 2010 winners’ papers) is available on the HOM SIGMAA website at http://www.homsigmaa.org/.

Thursday, October 21, 2010

Fractal Geometry


Benoît Mandelbrot, the father of fractal geometry, died last Thursday at the age of 85. We will learn about fractal geometry in class when we get to the modern era.

You can read more about it here.

Tuesday, October 12, 2010

Archimedes Palimpsest

Palimpsest comes from the Greek word palimpsestos meaning "scraped again". It is a manuscript that has another text written over it. Around 1200 A.D., a Christian monk turned Archimedes' book into a new prayer book. In October 1998, it was sold for $2 million at an auction. You can watch the documentary that we saw in class about the story again here: part 1 , part 2 and part 3.

Since 1998, a group of scientists have been working on the recovery of the writings of the greatest mathematician of the ancient era. You can find up to date information here.

As well, you can find a digital copy of the recovered Archamides Palimpsest after the prayers are removed on google books.

Monday, October 4, 2010

Dangerous Knowledge

“Dangerous Knowledge” is a fascinating documentary by the BBC about the story of four masterminds, Goerg Cantor, Ludwig Boltzmann, Kurt Gödel and Alan Turing. What do these four have in common?

Cantor created "set theory". Cantor’s Theorem says that there exist infinitely many infinite sets of different cardinalities. The theory was nonsense and shocking to some of the mathematicians of his time and it created a lot of opposition. Some philosophers saw his theory as a challenge to the uniqueness of “God”, the absolute infinity. Cantor is also known for the Continuum Hypothesis which states that there is no set with cardinality between the cardinality of natural numbers and of real numbers. (We will go over Cantor’s Theorem and the Continuum Hypothesis in detail in class). Cantor could neither prove nor disprove the Continuum Hypothesis. In 1940 and 1960 respectively, Kurt Gödel and Paul Cohen showed that, in fact, one cannot prove or disprove this hypothesis using the set theory axioms. Gödel is best known for his Incompleteness Theorem which states one cannot find a complete and consistent set of axioms for all mathematics. This gave a negative answer to Hilbert’s second problem. If you would like to know more about Cantor, Gödel, Boltzmann and Turing, watch this 90 minute documentary!