Abacus

From Wikipedia, the free encyclopedia

An abacus is a very old tool used for arithmetic. It is still used in some parts of the world. Sometimes blind people will use an abacus, because they can feel the numbers easily. The most common abacuses work by moving beads on rods.

Abacuses can do addition, subtraction, multiplication, division, and people can use them to find the square root of whole numbers. Expert, or very good, abacus users can sometimes do math quicker than basic calculators. There is a common Chinese abacus. This abacus is split into two basic rows, one row for the "5"s, and the bottom row for the "ones". There are one or two beads in the top row, and four or five beads in the bottom one. For example, 8 is one bead on top and 3 below, because 5 + 3 = 8. Every column represents a different digit.

Contents 1 Other websites 1.1 General and historical articles 1.2 Tutorials 1.3 Abacus curiosities

[change] Other websites

[change] General and historical articles

• Abacus Photos and Images
• Abacus
• Roman abacus

[change] Tutorials

• Manual de uso del Abaco Japonés Soroban
• Min Multimedia
• Suan Pan
• Abacus: Mystery of the Bead - an Abacus Manual

[change] Abacus curiosities

• Abacus in Various Number Systems at cut-the-knot
• Java applet of Chinese, Japanese and Russian abaci
• An atomic-scale abacus