Who invented the abacus?
It's a difficult to answer because the question is so vague. Perhaps you can rephrase the question after a brief history lesson.
The book, The Abacus by Jesse Dilson, St. Martin's Press, 175 Fifth Ave. New York, NY 10010 (US$12.95), is shrink-wrapped along with a wooden abacus.
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.
You can order one from Tomoe Soroban Corp. in Japan; their catalog is available on-line.
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?
In Toronto, try the following locations for abaci:
- S.U.P. Book Store
1571 Sandhurst Circle, Woodside Square #127-129,
- Sun Wa Book Store
280 Spadina Ave. Toronto. (416)-977-3457
- New World Book Store
442 Dundas St. W. Toronto. (416)-977-6029
Note: 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.
Students can build their own abacus
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 (an Origami box makes a neat frame, too); 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.
Leah Tait suggested this lesson plan about the abacus, with instructions for building an inexpensive abacus.
Edward Barinque created the a detailed how-to for building a popsicle-stick abacus.
Can you tell me how to multiply and divide using an abacus?Have a look at the Lee Abacus Manual or a portion of the Tomoe Soroban Abacus manual.
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.
For more details see, The Complete Book of Fingermath, Edwin M. Lieberthal, Fingermath International, ISBN: 0070376808.
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.
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.
I do my best to answer the volumes of email I receive, usually in batches every few months or so; however, answering the same questions repetitively is very tiresome. If the answer to your question isn't on this page or on any of the other pages, then it is likely I would have to do additional research to answer it.
If you haven't received a reply to your email, it's because I am busy; please be patient. However if you haven't heard from me in a while, it is possible I mis-filed your email; I do save all the abacus related email I receive.
I should also note that my interest in the abacus is purely academic; I am not a virtuoso abacus user and I do not consider myself an authority on the subject. These pages should not be taken as being authoritative on the subject of the abacus, though many have noted that they are the most comprehensive ones available on the web-- for that honour, I am grateful.
Can I link to your abacus website?
Yes, please go ahead and link. This website is hosted on a server in the Department of Electrical and Computer Engineering at Ryerson University in Toronto; I don't personally pay for bandwidth.
Please note that this website goes offline for 24 hours, once a year, in the last week of December.