The Abacus Online

2000
The abacus is one of the most clever mathematical tools ever invented. This site explores the abacus, particularly the Chinese (2/5) styled abacus or suan puan, and contains information on its history, tutorials on how to use it, and more. The site is available in 3 different languages: English, Russian, and Chinese. An underlying feature of the site is MyAbacusOnline, a personalized system in which the website will go along with your progress.