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How to use an Abacus

Diagram of a typical Chinese abacus set to zero - all heaven beads pushed up and all earth bead pushed down.

The Abacus utilizes a combination of two bases (base-2 and base-5) to represent decimal numbers. It is held horizontally with the smaller deck at the top. Each bead on the top deck has the value 5 and each bead on the lower deck has the value 1. The beads are pushed towards the central crossbar to show numbers. Working from right to left, the first vertical line represents units, the next tens, the next hundreds and so on.

So for example to show the number 9, on the first line, one heaven bead (top deck) would be moved down (representing 5 units) and 4 earth beads (bottom deck) would be moved up (each representing 4 units). To show the number 79, in addition to the beads in the first line used to make the number 9, one heaven bead would be moved down and two earth beads would be moved up on the second line, representing 5 tens and 2 tens respectively.

Addition on the abacus involves registering the numbers on the beads in the straight-forward left-to-right sequence they are written down in. As long as the digits are placed correctly, and the carry

Updated On: 18.09.30

1. On 30-Nov-2017, Anonymous wrote:
thanks it helped me a lot!:)

2. On 13-Jul-2016, Mooketsi wrote:
I would like assistance with manually calculating future values without using financial calculator.

3. On 09-Mar-2016, Kamau wrote:
am teaching abacus and i imported the abacus from china. this made the cost to go up making many patents not able to enroll.
where can i get abacus beads for me to assemble locally.this will cut the cost by 40%.
Possibles: craft/hobby store (they look like wood wheels); bead shop (jewelry, especially western/American Indian); Internet retailers of previous two; Chinese Internet giant Alibaba might have vendors of the components you seek.
Walking into the 1st two with your abacus might get them to dig out a catalog.

4. On 29-Dec-2014, Anonymous wrote:
Since the two heaven beads add to 10, and there are still the five earth beads, which means all of the beads towards the centre sums to 15, is it therefore possible to use the abacus for hexadecimal arithmetic?
• On 03-Dec-2016, Wle replied:
hex, yes i think so.. though it might be better if they would sum to 16

5. On 29-Dec-2014, Anonymous wrote:
Am I correct then that the abacus that is a logo for this, the educalc.net site, reads 668 200 (six hundred sixty eight thousand and two hundred) and/or \$6682.00, Euro, HRK, pounds, yen, rubles or whatever local currency floats ones boat? I have often seen abacuses (abaci? abacodes?) where there is also a bar running perpendicular for a decimal point, separating units from the tenths and hundreths, and naturally one without that bar can be used in the same way, or with the decimal point anywhere else...

I attended mathematical workshop on the us of the Chinese abacus and could not understand anything until I read this ppiece on the web thanks alot.

7. On 10-Sep-2013, Anonymous wrote:
can anyone tell me why it is called the heaven and earth beads
• On 11-Sep-2013, Peter Tong replied:
I could only guess that the ancient Chinese like to name things that is place on the top "heaven".

8. On 16-Jul-2013, Anonymous wrote:
i’m a math teacher and I find it hard to use it... I believe it’s hard for first timers.
• On 06-Sep-2014, 4B replied:
An abacus isn\'t a calculator where you just punch numbers. Think of it as a computer game--you have to learn how to play it!
I agree with both of you. Yet, decades ago was a film clip of someone adding two large numbers and he beat another person punching the numbers into a calculator. (Reply)

9. On 27-Jun-2013, Ray wrote:
I have an Abacus given to me, that looks exactly like the one in the photo on your page. The third row in from each end, is a copper (?) rod which is thinner than the others. The others appear to be wood, or bambo. Are the copper rods only for structure, or do they have another purpose? My Abacus also has the same exact brass (?) corner brackets and the exact ornate brass (?) brackets that hold the divider bar in place. Could my Abacus be old? I do not know its origin.
• On 06-Sep-2014, 4B replied:
Late to reply but your comment (antique appraisal) really isn\'t relevent to the discussion on how an abacus works.
• On 27-Oct-2014, Anonymous replied:
what does that have to do with how to use an abacus ??