Coins and Numbers in Aropa

The Aropans have developed a system of numbers based in part upon their coinage structure. The coins are standard Rolemaster quarter-ounce mint throughout all of Aropa, and follow the standard 10-1 ratio, but use the Treasure Companion ordering (i.e. Mithril coins are worth 1,000 gold, whereas aluminum coins are worth 100 gold). From greatest value to least, the coins are:

Mithril (only for ceremonial purposes)
Aluminum (rare)
Platinum
Gold
Silver
Bronze
Copper
Tin
Iron (no longer used)

In the early years of Annos (before 750 Y.A.), there were intermediate "coins" that were worth 5 of the smaller coin (or half of the larger coin). In one case (the fur piece), there was no actual coin, but referred to the value of a standard fox pelt. In the case of the eog (truesteel) and laen (trueglass) pieces, these do not exist, but the names are used as placeholders for the numeric system. (They were discovered after the basic system was in place, and represent lower numeric values than mithril, which had been discovered, even though they are worth more than mithril alchemically.) These values are:

Eog (between Mithril and Aluminum)
Laen
Zinc
Jade
Fur
Nickel
Half-copper (origin disputed, but refers either to a crude attempt to alloy copper or a practice of slicing copper coins in half to make change)
Quartz

These 17 values form the basis of the numeric system. The first letter of the smallest value (I), represents a numeric value of 1. The next higher letter, Q (for Quartz), represents 5. Each value then builds up, to the point where Mithril, the largest actual coin, represents a value of 100 million. No provisions have yet been made for larger numbers.

The Aropan system uses subtracive values similar to the Roman numeral system of Earth, but supports the concept of complex subtraction. Aropans use "IQ" to represent the number 4, just as Roman numerals allow "IV" to represent the same thing, but the Aropans allow for subtractions to cross boundaries of order of magnitude. "IB" would be 999 (1,000 - 1), a value that Roman numerals would list as "CMXCIX". Additionally, sometimes a value can be built up (using normal addition rules for numbers) only to be subtracted from an even larger number. This is seen in the current Year of Annos BCTTQNI. "B" represents 1,000, "CTTQ" represents 125, but immediately precedes "N", which represents 500. Thus "CTTQN" represents 375 (500 - 125). Combining all the results (1,000 + 375 + 1), we see that the BCTTQNI represents the year 1376.