| Abacus |
 |
| "The abacus is still in use today by
shopkeepers in Asia and "Chinatowns" in North
America. (The photograph on the right was taken in a
store in Beijing, China in September 1997, and shows a
clerk using the abacus . Photo is courtesy Peter Wouda.)" |
| Source:
Luis Fernandes, "The
Abacus, the Art of Calculating with Beads" |