Jesús Cabrera: Jesús Cabrera, retired (astro)physicist, spent the
better part of a year writing two Wikibooks and a 360 page PDF document called
'THE EASTERN ABACUS - A Guide to Bead Arithmetic.' Many thanks to Jesús for
these wonderful contributions.
His Soroban Trainer web app includes some traditional or
Chinese division (kijoho) exercises . See below in
Learning Resources.
Totton Heffelfinger:
The following techniques were taught to me by members of the
Soroban/Abacus newsgroup. In particular, I'd like to thank Torsten Reincke
whose contributions bring us all to a greater understanding and more
thoughtful use of abacus.
Hannu Hinkka: Russian
Multiplication - an old technique that requires no multiplication tables.
Fabrice Bouillerot: Fabrice shares his very interesting technique
for using complementary numbers while solving problems of long division.
Merci beaucoup, Fabrice. Division by
Complementary Numbers (DCN)
Milton Zuluaga: Milton shares a marvelous multiplication
technique taught to him by the Cultural Attaché of the Chinese Embassy
in Colombia (South América) back in 1996.
Multiply 316 X 29 - this link will take you off site to Goggle Drive
THE OTHER SIDE; NEGATIVE NUMBERS
Masaaki Murakami:
The Other Side of Soroban- A guide to adding, subtracting, multiplying and
dividing Negative Numbers
Fernando Tejón: Techniques for using complementary numbers: one technique
simplifies problems of subtraction; the other solves problems of subtraction where
the resulting answer is a negative number. Complementary
Numbers
Shane Baggs: This is an excellent presentation of a very powerful technique
for finding the cube root of a number. Many thanks to Shane for all of his hard work
and research and for updating this method for all of us to use.
Japanese Cube Root Algorithm
Masaaki Murakami:
Square Root by Half Square with Kijoho.
This JavaScript application will guide you, step by step, in solving square
roots on the abacus by Prof. Kato's method and using Chinese division (kijoho).
You can download it to your computer from its
GitHub repository, or launch it
directly into your browser from
here.
LOGARITHMS
Deji Adegbite: Thanks to Deji who's done an exceptional job in illustrating
his techniques for calculating logarithms on a soroban.
Marcos Labriola: Marcos kindly shares these powerful techniques
that illustrate how easy it is to alternate between Decimal, Binary and
Octal number systems. Thank you Marcos.
Jesús Cabrera:
A Short Guide to the 5th (lower) bead In this excellent tutorial
Jesús shows us how to efficiently make use of the 5th lower bead on
a 1:5 bead soroban.
Totton Heffelfinger:
The following techniques were taught to
me by members of the Soroban/Abacus newsgroup. In particular, I'd like
to thank Torsten Reincke whose contributions bring us all to a greater understanding and more
thoughtful use of abacus.
Print
Abacus.pdf - Some experts recommend using this aide to help visualize an
abacus. Place the printed abacus on the desk and visualize solving problems.
It's important to actually move the fingers as if doing calculations on a real abacus.
Explanation of the two kanji characters that make up the word soroban.
Master Craftsman: While the process of making
soroban has become largely mechanical, here are 7 extraordinary YouTube videos
showing a master craftsman hand crafting soroban. The narrator explains the
process in Japanese but the videos need little or no explanation. ▪
Link to the 7 YouTube videos
Early Calculation
(5.61 mb PDF File) - off site link to very interesting 56 page article featuring many
early calculating methods and devices. Thanks to both Ed Thelen and Michael R. Williams.
CONTRIBUTIONS
The following have been contributed by members of the Soroban/Abacus newsgroup. Thanks to Edvaldo, Fernando,
Shane & Fabio for sharing these files with us.
Soroban Trainer: A
Soroban/abacus training web application in JavaScript by Masaaki Murakami that
will allow you to use a beautiful simulation of 4/1, 5/1 and 5/2 type abacuses
(with the possibility of using the suspended bead!) and also offers you a series
of traditional division exercises (Kijoho). You can download it to your computer from its
GitHub repository,
or launch it directly into your browser from
here. For
mobile devices you can try
this other version that doesn't require a keyboard to manipulate the suspended bead.
Dave Bernazzani: Last but by no means least. Dave is the man who got all of this started for me and for so many
others. In 2001 a search of the internet took me to Dave's excellent Soroban/Abacus Handbook. I'd found my
first
teacher. Since switching ISPs in May 2006 Dave's Handbook has been offline. He offers his handbook here in PDF (Adobe Acrobat) format.
▪ Dave Bernazzani's Soroban/Abacus
Handbook (281 kb PDF File)