Monday, May 25, 2015

abacus - simple as 123... 456789



The abacus is far simpler to understand than I imagined before. For some reason I always assumed the abacus was like roman numerals or 5 count hash marks (where you make 4 vertical lines and then a diagonal 5th for every 5 you count).

It's actually very simple. Each vertical row of beads is a single digit. The beads on the bottom are worth 1 each. The beads on the top are worth 5 each. The bottom and top aren't separate, they are added together to form a single digit.

The pictured above is a Chinese abacus. There are many different types from all around the world. The Russian abacus just has 10 beads for each column rather than having separate beads for ones and fives.

Check out this simple simulator for a Chinese abacus. Just click on the beads and it should become crystal clear exactly how it all works.


MISC

  • Cecchetti, Enrico
    • Italian ballet dancer and teacher.
  • Cecil (of Chelwood), (Edgar Algernon) Robert Gascoyne
    • Cecil, 1st Vicount - British politician against Japan & Nazis before that was cool.
  • Cecil, William; 1st Baron Burghley
    • Honest adviser to queen Elizabeth in 1500's.
  • Cecrops
    • Greek. First king of Attica.
  • cecum
    • 1st part of large intestine. Larger in plant eating animals. Smaller in meat eaters. Contains bacteria to digest cellulose.

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