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Fingers find Fermat’s factorisation most probable

Published online by Cambridge University Press:  25 August 2015

Randall Baumback
Randall Baumback*
Affiliation:
James Logan H.S., Union City, Ca 94587 USA Ohlone College, Fremont Ca, USA
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Extract

“I know my ones. I know my twos. I know my threes… Ah, the finger man.” An unforgettable exchange between a defiant, remedial student, and a confident, driven math teacher in the movie Stand and Deliver [1]. This back-and-forth exchange presented a teachable moment for the determined teacher giving way to a class presentation of the finger manipulation for multiplying by nine, a technique familiar to most every elementary school student in the U.S. Little did I know this simple idea would lead to the heuristic thinking outlined in the sequence of topics below connecting Fermat and finger multiplication.

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Type
Research Article
Information
The Mathematical Gazette , Volume 98 , Issue 543 , November 2014, pp. 452 - 458
Copyright
Copyright © The Mathematical Association 2014

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References

1. Keogh, T., Stand and deliver, IMDb, accessed August 2010 at http://www.imdb.com/title/tt0094027/amazonl Google Scholar
2. Eyler, M. and Valero, V., Multiplying by nine using your hands, YouTube. November 13, 2008, http://www.youtube.com/atch?v=CVbcra3rCqc (accessed August 13, 2010).Google Scholar
3. Baumback, R., Finger Multiplication: A Mathematical Excursion, https://sites.google.com/site/rbaumback/publications-papers-l (accessed June 25, 2012).Google Scholar
4. Wikipedia, Fermat’s factorization method, accessed June 2013 at http://en.wikipedia.org/wiki/Fermat%27s_factorization_method Google Scholar
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