Etruscan numerals whether the numbers on opposite faces of Etruscan dice add up to seven, like nowadays. Some dice found did not show this proposed pattern. An aspect of the Etruscan numeral system is that some numbers, as in the Roman system, are represented as partial subtractions. So "17" is not written *"semφ-śar" as users of the Arabic numerals might reason. One instead finds "ci-em zaθrum", literally "three from twenty". The numbers 17, 18 and 19 are all written in this way. The general agreement among Etruscologists nowadays is the following (except about which of huθ and śa were "four" or "six",
Sicherman dice American". The numbers can be arranged so that all pairs of numbers on opposing sides sum to equal numbers, 5 for the first and 9 for the second. Later, in a letter to Sicherman, Gardner mentioned that a magician he knew had anticipated Sicherman's discovery. For generalizations of the Sicherman dice to more than two dice and noncubical dice, see Broline (1979), Gallian and Rusin (1979), Brunson and Swift (1997/1998), and Fowler and Swift (1999). Let a "canonical" "n"-sided die be an "n"-hedron whose faces are marked with the integers [1,n] such that the probability of throwing each number is