Can I link to your abacus website?
Yes, you have my permission to link to the website. This website is hosted on a server in the Department of Electrical and Computer Engineering at Ryerson University in Toronto so I don't personally pay for the bandwidth.
Also note that this website goes offline for 24 hours, once a year, sometime in the last week of December. If it's down, try again the following day.
Who invented the abacus?
It's a difficult question to answer because the question is so vague (which abacus are you referring to?). Perhaps you can rephrase the question after a brief history lesson on the origins of the abacus as we know it today.
Here is a selection of books that will be helpful to the beginner, intermediate and advanced abacus user.
EasyAbacus by Edward Barnique, Trafford Publishing, written for grades 4-6, or anyone interested in learning the basics.
The Abacus by Jesse Dilson, St. Martin's Press, (US$12.95), is shrink-wrapped along with a wooden abacus.
Japanese Abacus: It's Use and Theory, by Takashi Kojima, Charles E Tuttle Co., ISBN: 0804802785
Advanced Abacus: Japanese Theory and Practice, by Takashi Kojima, Charles E Tuttle Co., ISBN: 0804800030 (thanks to Patrick C.W. Pang for this reference).
I have no affiliation (financial or otherwise) with any of these products or places, nor do I have any information regarding volume sales of abaci.
- The book, The Abacus by Jesse Dilson, St. Martin's Press, (US$12.95), is shrink-wrapped along with a wooden abacus (please see previous question, above).
- You can order one from Tomoe Soroban Corp. in Japan; their catalog is available on-line.
- Shop around the Chinatown in your city. It is possible to get inexpensive abaci for less than $2.00. I don't know any distributors so I cannot recommend any.
- The Cranmer Abacus is available from the American Printing House. One cool feature of this abacus is that several abaci can be coupled together to provide additional columns.
I'm a teacher and want to buy a number of abaci for my class. Do you know where I can buy some inexpensive ones?
Rather than buying abaci, have the students build their own abacus as a class project, with various items they bring from home (or purchased in a craft store); e.g. popsicle-sticks to build the frame; drinking straws or pipe-cleaners for the rods; machine nuts or washers, macaroni, Cheerios (preserved with some thinned glue and poster paint) or plastic decorative jewellery beads for the abacus beads. It's both a learning experience and a lot of fun.
- Edward Barinque created the a detailed how-to for building a popsicle-stick abacus.
- LEGO fans can build a LEGO abacus.
- Leah Tait suggested this lesson plan about the abacus, with instructions for building an inexpensive abacus.
Can you tell me how to multiply and divide using an abacus?
Finger Math, also known as Chisan-Bop, developed by Korean school teacher Sung Jin Pai, is a technique of performing high-speed arithmethic using ones fingers. It uses the fingers of the right hand to represent the numbers 1-4, right thumb as 5; the fingers of the left hand as 10s, the left thumb as 50.
It requires two hands. Try it yourself first. Place your hands palm-down on a table, fingers spread. That's zero. Now make two fists. Your calculator now reads 99, the highest value. Reading from left to right now, each of the four fingers on your left hand equals ten; the left thumb equals fifty; the right thumb equals five; and each of the four fingers on your right hand equals one.
Now construct different numbers on your own. Two thumbs folded under could only equal 55; two index fingers, 11.
Let's try a sample problem: 18 + 26. Show 18 by pressing down the left index finger and the right thumb, index, middle, and ring fingers. Now: Think of 26 as 10, 10, 5, and 1. The first two 10s are easy: Press down the middle and ring fingers on your left hands. The 5 is the only tricky part; you exchange between hands. Lift the right thumb (subtracting 5), then press down your left pinky (adding 10, for a net gain of 5). For the 1, press down the right pinky. Your hands now read 44—the correct answer!
—Copyright 1991, Steve J. Bennett and Ruth I. Loetterle Bennett.
For more details see, The Complete Book of Fingermath, Edwin M. Lieberthal, Fingermath International, ISBN: 0070376808.
What kind of abacus has beads that slide left/right not up/down?You probably have a Russian abacus, known as a schoty.
Are there any schools that teach the abacus?
Toronto, contact Theresa Lee:
4465 Sheppard Avenue East, Suite 207
Scarborough, Ontario M1S 5H9
Phone: (416)-298-7323 OR (905)-471-4877
You may wish to contact these schools to inquire whether they can recommend someone in your area. Alternatively, contact your local Chinese or Japanese embassy/consulate and inquire about schools in your area.