Award winning site by Luis Fernandes; Ryerson University, Toronto, Ontario, Canada. Historical timeline, early counting boards, various styles of the abacus. Java applet simulates real time use of the abacus. Links to other information.

Teaches you how to use the Abacus. Also has introduction to Chinese numerals and formulas. Select the Amazing Abacus when you reach the Home Page.

ThinkQuest: Interactive Lessons on how to use the abacus. Site is a little slow but very clear in terms of how to use the abacus.