Editing Abacus (section)

=== Rome ===
{{Main|Roman abacus}}
[[File:RomanAbacusRecon.jpg|right|thumb|Copy of a [[Roman abacus]]]]
The normal method of calculation in ancient Rome, as in Greece, was by moving counters on a smooth table. Originally pebbles ({{Langx|la|calculi}}) were used. Marked lines indicated units, fives, tens, etc. as in the [[Roman numeral]] system.

Writing in the 1st century BC, [[Horace]] refers to the wax abacus, a board covered with a thin layer of black wax on which columns and figures were inscribed using a stylus.<ref name=rome>{{harvnb|Ifrah|2001|p=18}}</ref>

One example of archaeological evidence of the [[Roman abacus]], shown nearby in reconstruction, dates to the 1st century AD. It has eight long grooves containing up to five beads in each and eight shorter grooves having either one or no beads in each. The groove marked I indicates units, X tens, and so on up to millions. The beads in the shorter grooves denote fives (five units, five tens, etc.) resembling a [[bi-quinary coded decimal]] system related to the [[Roman numerals]]. The short grooves on the right may have been used for marking Roman "ounces" (i.e. fractions).