For centuries the abacus ruled as the calculator for traders and merchants the world over. Today, much of the world now embraces new technology and the once mighty abacus has been replaced with solar-powered calculators and excel spreadsheets. Yet in some places, the abacus is still used as a learning tool for elementary school students and as a method of calculation for traders.
Though many cultures have used the abacus throughout the years, the two most common types that exist today are the Japanese abacus (called soroban) and the Chinese abacus (called suanpan). The main difference between the two is the Japanese abacus has one row of beads on the top deck where the Chinese has two rows, allowing the suanpan to compute to hexadecimal.
This abacus is modeled after the suanpan.
If you're in the mood to nerd it up, check out some of the other types of abaci used over the years.
The simplicity of this 'computer' belies the complexity of computations achievable. Word on the street is there are techniques to solve for square and even cube root using the abacus!
(this instructable also covers elementary arithmetic, jump to step 7 to see.)
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enough talk, let's abacus!
Step 1: A brief introduction
The upper deck of 2 rows of beads are called heavenly beads
The lower deck of 5 rows of beads are called earthly beads
The beads are counted by moving them up or down towards the centre bar, the abacus is read from left to right and each column corresponds as a zero placeholder (each column can represent a factor of 10). The decimal location is defined by use, or can be marked on the frame (a low-tech option would be an elastic around the frame to indicate your decimal).
The earthly beads (lower deck) are counted up to reach 5, to continue counting one heavenly bead (upper deck) is pushed down to represent 5 and the remaining earthly beads are pushed back down and counted up once again to reach 10. The process is continued on to the next column.
(using the second row of beads in the upper deck is covered in step10).