The Abacus

How to Use an Abacus

Before I begin describing how to use an abacus, I ought to specify that there really is not just one, quintessential abacus.  In general, there are three types of abaci: dust, counter, and frame.  (These categories are suggested in passing by Gardner, Smith, and Williams, but I would like to establish them formally in my final paper.)  The dust abacus was a dustboard (defined in post) with columns for place value marked, and Hindu numerals (excluding zero) written in these columns (Ifrah, 2000).  This method is only a few steps from the modern pen-and-paper method.

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