Early English Currency, Roman Numerals for Dates and Currency, and Tally Sticks
The standard unit of currency since medieval times has been the pound (£). A pound was 20 shillings (s), and a shilling was 12 pence (d, for denarius or the Roman penny), so a pound also was equivalent to 240 pence. Because the early currency was not "decimalized," you had to add up each unit of currency separately in this format: £ 2.11.3 (using modern Arabic numbers--see below), which would be spoken "two pounds, eleven shillings and three pence," or "two-pounds-eleven-three." When adding, you would add each unit separately, then convert pence to shillings (with leftover pence in the right position), convert the resulting total shillings to pounds (with leftover shillings in the central position), and add up the total pounds. The British resisted decimalization (one pound = 100 pence and that's that) until 1971. That is the force of cultural tradition. English currency was medieval until after the Beatles broke up!
Here is the currency in table form with some nicknames and three additional coins minted prior to the nineteenth century but now no longer produced.
£ pound "quid"
s shilling "bob"
d pence "copper"
m mark 2/3 £ or 13s 4d
angel 10s or 1/2£ (Renaissance and later)
guinea 1 £ . 1 s (Renaissance and later)
six-pence "tanner" (Renaissance and later)
Medieval scribes wrote numbers using Roman numerals, which you should have learned in a grade school history class but, for that very reason, you may have forgotten. Today, only the American Superbowl and construction year inscriptions on public buildings seem to require some feeble knowledge of Roman numerals. For that reason, in medieval wills and literary texts, you have to be shift gears to read characters like "xx" or "iiij" as numbers, not very, very odd words. First, a refresher on Roman numerals. Ordinarily they read in the same left-to-right order that modern Arabic numbers do, but if a lower number precedes a higher number, you subtract it from the higher number.
The character "i" is one, but don't confuse it with "l" (lower case L), which is fifty. Numbers from 1 to 3 are written by adding "i"s, like "ii," and "iii." At 4, the Roman convention uses a shift in position to indicate the value of an initial lower number is subtracted from the higher "v" or 5, like this, "iv," though sometimes Medieval scribes violate the convention and just give you this, "iiii." Scribes sometimes broke the "iv" rule by writing "iiij," using the final "j" to help the eye group and count the single strokes of the ones. So "iiij s." would be "four shillings." The numbers from 5 to 8 add "i"s to the "v" (v, vii, viii) until 9, which subtracts "i" from "x" or 10, like this "ix." Counting upward to xx, or 20, goes like this: x, xi, xii, . . . xx.. Fifty is "l." One hundred is "c." One thousand is "m." To the best of my knowledge, the Romans did not reckon in millions, and they certainly did not have the political audacity to run national budget deficits in the trillions. Dates on early printers' title pages (until the C19) typically were written in capital Roman numerals. For instance, to indicate 2004, the year in which this web page was created, a printer would set the type "MMIV" or "MMIIIJ" (see below for that one).
Combining the Roman counting lesson with the currency abbreviations, we can now describe what you will see in medieval texts that count things. When the scribe writes "xx men," he means "twenty men." When the scribe writes "ii d," he means "two pence." Using the "LSD" formula for prices and costs, an item might be said to be worth "£ ii s iv d iij" or "two pounds four shillings and three pence," or even just "ii.iv.iij," without the symbols in fast note-taking, as on the flyleaf of a book when a collector tallies up her/his expenses. Now you know why the English economy became easier for Americans to negotiate after 1971 when "decimalization" made all English pounds worth one hundred pence and they did away with the shillings, guineas, marks, groats, and other colorful relics of Medieval commerce.
Medieval merchants and ordinary people had to keep financial records just like we do, but they did not have access to database programs or calculators. Nevertheless, they were able to track their debts and credits by carving the numbers into a tally stick.