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.

Heaven beads, each worth 5

Earth beads, each worth 1

Try the on-line Abacus

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: 15.07.28

  1. On 10-May-2018, Emo Emu wrote: 
    prucci be gucci
    Your reply to Emo Emu

  2. On 10-May-2018, Emo Emu wrote: 
    prucci be gucci
    Your reply to Emo Emu

  3. On 17-Feb-2018, Liz wrote: 
    any HP48 connectivity for Linux?
    Your reply to Liz

  4. On 30-Nov-2017, Anonymous wrote: 
    thanks it helped me a lot!:)
    Your reply to Anonymous

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

  6. 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%.
    Your reply to Kamau
    • On 10-Mar-2016, Cliffontheroad replied: 
      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.
      Your reply to Cliffontheroad

  7. On 26-Oct-2015, Boberto wrote: 
    YOLO Swag
    Your reply to Boberto

  8. On 11-May-2015, Anonymous wrote: 
    Type your message here...Pls Can Sm1 Enlight Me Mre On Dis Abacus Wit D Help Of Diagram
    Your reply to Anonymous

  9. 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?
    Your reply to Anonymous
    • On 03-Dec-2016, Wle replied: 
      hex, yes i think so.. though it might be better if they would sum to 16
      Your reply to Wle

  10. On 29-Dec-2014, Anonymous wrote: 
    Am I correct then that the abacus that is a logo for this, the 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...
    Your reply to Anonymous

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In reply to Boberto, who on 26-Oct-2015 wrote:


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