Abacus

Abacus (different historical Abaci) Android source: AbacusApp.zip.

Unzip somewhere and then put in Eclipse like File->Project->Android Project from Existing Code. Then build, install, and run as usual. Any trouble building and getting on your Android, let me know so I can make fixes or better instructions.

Android executable: AbacusApp.apk.

See project notes for todo list and history.

Click on a abacus below to run Java Abacus (need Java 7 JVM) written mostly by David Bagley. Icons below are all "zeroed out" to give a rough idea on what to expect.

Configurations (+ menu interface)	Applet
Chinese Abacus (also available Korean, Japanese, Roman, Russian, Danish)
Lee's Abacus Principal Chinese with a Noneven Distributed 7 Rail Auxiliary
Lee's Abacus Principal Korean with a Noneven Distributed 7 Rail Auxiliary
Lee's Abacus Principal Chinese with a Even Distributed 9 Rail Auxiliary

The simplest configurations are the below static versions. The menu interface control has been taken out (except for some non-base 10 examples). This control feature is available in the menu versions above. The control interface lets you change formats easily. However, the static versions can be modified by clicking on the abacus itself, then, for example, "i" and "d" will increase and decrease the number of rails and "f" will change formats.

Static Configurations	Applet
Chinese Abacus (Saun-pan)
Korean Abacus (Supan, AKA Japanese Soroban pre-WWII)
Japanese Abacus (Soroban post-WWII)
Roman Hand Abacus right most column twelfths and Ancient Roman Numerals in display
Roman Hand Abacus right most column eighths and Modern Roman Numerals on abacus
Russian Abacus (Schoty)
Old Russian Abacus (Schoty w/ 1/4 Kopek)
Georgian Abacus (Russian base 20, for warmer climate (no shoes), do not take seriously)
Danish School Abacus
Medieval Counter
Mesoamerican Abacus (Nepohualtzintzin, similar to Japanese base 20)
Babylonian Watch (proposed by author)
Chinese Solid-And-Broken-Bar System (base 12)
Base 16 Abacus (Japanese base 16)
Lee's Abacus Principal Chinese with a Noneven Distributed 7 Rail Auxiliary
Lee's Abacus Principal Korean with a Noneven Distributed 7 Rail Auxiliary
Lee's Abacus Principal Chinese with a Even Distributed 9 Rail Auxiliary

There are two modes in menu that will help you learn how to use the abacus:

the "demo" mode: here some static lessons are given for the different types of abacus. The lessons include counting, adding, subtracting, and multiplying. The original lessons were taken from work by Luis Fernandes.

the "teach" mode: here you learn at your own pace by entering your own calculation like "A+B", "A-B", "A*B", or "A/B" (where A>0 and result positive). Pressing the enter key, will give you a step by step explanation and show proper moves on the abacus. According to the books below, you are supposed to start on left side, when adding or subtracting multi-digit numbers. (There is a menu option "rightToLeftAdd", if you think this is inefficient (similar one for multiplication "rightToLeftMult")). Lee's Abacus is more suitable if you are learning multiplication and division, as there are extra places to store operands.

SQRT operation is a feature that that solves perfect squares (0 - 104080804 tested with internal tester) in teach mode and also handles floating point numbers. For non-perfect squares it gives approximations. Move the decimal point slider to the left before starting to increase precision. Try it out with "10201v" in teach mode on a "Lee's Abacus". Unlike the other operations, sqrt reduces to an answer from which you must divide by 2. (You can try that out like "202/2", once sqrt operation gives you its "doubled" answer). This follows closely the work of Lee Kai-chen from his book "How to Learn Lee's Abacus". Let me know of any problems. Now if you can just input negatives... the solution would involve turing the abacus sideways. ;)

CBRT operation is a brand New

feature that was just added. It solves perfect cubes (0 - 1003003001 tested with internal tester). Try it out with "1030301u" in teach mode on a "Lee's Abacus". Here cbrt reduces to an answer from which you must divide by 3. (You can try that out like "303/3", once cbrt operation gives its "tripled" answer.) This again follows closely the work of Lee Kai-chen.

You can download the jar file (preserve the .jar extension), and then it can be run as an application like "java -jar AbacusApp.jar -rails=15" or "java -jar AbacusApp.jar -lee=1 -leftAuxRails=9 -rightAuxRails=9". The X Manual Page is written for the X version but may be useful to understanding the Java program.

Source Code	X Manual Page	Javadoc	Jar File
abacus.zip	xabacus	AbacusApplet	AbacusApp.jar

See project notes for todo list and history. Please let me know if I left out anything.

There is a New

feature for teachers to test students on the use the abacus. Below, is a demo only as you would need to run as application to have the full feature. The full feature would give the ability to create your own tests. Results would go into a results directory. Sample tests are given in zip file (there is only the one test so far, in demo below). The idea is to move the beads to the correct position and then record the answer by a certain time.

Test Configuration	Applet
Japanese Abacus (Soroban post-WWII)

Manual for xabacus, see table above.

C/C++ Source Code for X and Windows (xabacus 8.0.3, bzip2'd file)

xabacus at tux.org (http)

xabacus at tux.org (ftp)

xabacus at ibiblio.org

C/C++ Source Code and Binary for Windows (wabacus zip'd file, same source as above compiled with MinGW).

wabacus (Windows abacus)

Short story by Isaac Asimov The Feeling of Power

Abaci

Android Abacus

Java Abacus

X Abacus

More Abacus stuff