The Abacus: The art of calculating with beads Three abacii
Scientific American 2003 Sci/Tech Web Awards

Selected by Scientific American as a winner of the 2003 Sci/Tech Web Awards.



Construction  ·  Basics  ·  Java Applet  ·  Technique  ·  The Abacus Today


Timeline  ·  Salamis Tablet  ·  Counting Board  ·  Roman Hand Abacus  ·  Suan Pan  ·  Soroban  ·  Schoty  ·  Nepohualtzitzin  ·  Khipu  ·  Lee Abacus

Interactive Abacus Tutor

Sarat Chandran and David A. Bagley's incredible Java abacus with a built-in tutor for counting, addition and subtraction.


Addition  ·  Subtraction  ·  Multiplication & Division  ·  Square Roots  ·  Cube Roots

The Lee Abacus

The manual for the Lee Abacus, c. 1958 is available as Text

The Abacus as Art

Michael Mode builds exotic abaci as art objects.

Abacus: Mystery of the Bead

Abacus Techniques by Totton Heffelfinger & Gary Flom.

* Articles, Excerpts and Analysis

The Abacus vs.The Electric Calculator

In 1946, a contest held in Tokyo, pitted an abacus against an electric calculator; the abacus won, of course.

Feynman vs. The Abacus

Richard Feynman battles against the abacus; the result is not surprising (if you know Feynman).

Comparing the Chinese and the Mesoamerican Abacus

An analysis contributed by David B. Kelley.

The Roman Hand-Abacus

An analysis contributed by Steve Stephenson.

Ancient Computers

Steve Stephenson contributes another analysis on the Salamis Tablet and the Roman Hand-Abacus and proposes a theory on how these devices evolved.

Using a Counting Board

In this video, Steve Stephenson explains how to use a Counting Board like the Salamis Tablet.

The Incan Khipu

String, and Knot, Theory of Inca Writing by John Noble Wilford.
Talking Knots of the Incas by Viviano and Davide Domenici.

Lost Tribes, Lost Knowledge

An article about the dangers of forgetting knowledge learned from the past, by Eugene Linden.

* All Things Abacus

Additional Abacus Resources

Purchase  or build an abacus  ·  An abacus for your Palm  ·  Books about the abacus  ·  Java applet source code  ·  The Mesoamerican abacus

Resources For Teachers

The abacus in the classroom  ·  Abacus lesson plan  ·  Math and science resources for teachers


High-resolution photos of my abacus collection.