The notion of number and of counting, as well as the names of the smaller and more-often-used numbers, date back to prehistoric times and I don't believe that there is a tribe of human beings on Earth today, however primitive, that does not have some notion of number.
With the invention of writing (a step which marks the boundary line between "prehistoric" and "historic"), the next step had to be taken-numbers had to be written.
One can, of course, easily devise written symbols for the words that represent particular numbers, as easily as for any other word. In English we can write the number of fingers on one hand as "five" and the number of digits on all four limbs as "twenty."
Early in the game, however, the kings' tax-collectors, chroniclers, and scribes saw that numbers bad t-he pe culiarity of being ordered. There was one set way of count ing numbers and any number could be defined by counting up to it. Therefore why not make marks which need be counted up to the proper number.
Thus, if we let "one" be represented as ' and "two" as and "three" as "', we can then work out the number indicated by a given symbol without trouble. You can see, for instance, that the symbol stands for "twenty-three." What's more, such a symbol is universal.
Whatever language you count in, the symbol stands for the number "twenty-three" in whatever sound your par ticular language uses to represent it.
It gets hard to read too many marks in an unbroken row, so it is only natural to break it up into smaller groups. If we are used to counting on the fingers of one hand, it seems natural to break up the marks into groups of five.
"Twenty-three" then becomes "' @" 'if" fl@lf "f. If we are more sophisticated and use both hands in counting, we would write it fl"pttflf '//. If we go barefoot and use our toes, too, we might break numbers into twenties.
All three methods of breaking up number symbols into more easily handled groups have left their mark on the various number systems of mankind, but the favorite was division into ten. Twenty symbols in one group are, on the whole, too many for easy grasping, while five symbols in one group produce too many groups as numbers grow larger. Division into ten is the happy compromise.
It seems a natural thought to go on to indicate groups of ten by a separate mark. There is no reason to insist on writing out a group of ten as Ifillittif every time, when a separate mark, let us say -, can be used for the purpose.
In that case "twenty-three" could be written as - "'.
Once you've started this way, the next steps are clear.
By the time you have ten groups of ten (a hundred), you can introduce another symbol, for instance +. Ten hun dreds, or a thousand, can become = and so on. In that case, the number "four thousand six hundred seventy-five" can be written - ++++++
To make such a set of symbols more easily graspable, we can take advantage of the ability of the eye to form a pattern. (You know how you can tell the numbers displayed by a pack of cards or a pair of dice by the pattern itself.)
We could therefore write "four thousand six hundred sev enty-five" as
And, as a matter of fact, the ancient Babylonians used just this system of writing numbers, but they used cunei form wedges to express it.
The Greeks, in the earlier stages of their development, used a system similar to that of the Babylonians, but in later times an alternate method grew popular. They made use of another ordered system-that of the letters of the alphabet.
It is natural to correlate the alphabet and the number system. We are taught both about the same time in child hood, and the two ordered systems of objects naturally tend to match up. The series "ay, bee, see, dee…" comes as glibly as "one, two, three, four…" and there is no dif ficulty in substituting one for the other.
If we use undifferentiated symbols such as '" for ggseven," all the components of the symbol are identical. and all must be included without exception if. the symbol is to mean "seven" and nothing else. On the other hand, if "A,BCDEFG" stands for "seven" (count the letters and see) then, since each symbol is different, only the last need be written. You can't confuse the fact that G is the seventh letter of the alphabet and therefore stands for "seven." In this way, a one-component symbol does the work of a seven-component symbol. Furthermore, " (six) looks very much like "' (seven); whereas F (six) looks n6th ing at all like G (seven).
The Greeks used their own alphabet, of course, but let's use our own alphabet here for the complete demonstration:
A = one, B = two, C = three, D = four, E Five, F six, G = seven, H = eight, I = nine, and J = ten.
We could let the letter K go on to equal "eleven," but at that rate our alphabet will only help us up through "twenty-six." The Greeks had a better system. The Baby lonian notion of groups of ten had left its mark. If J ten, then J equals not only ten objects but also one group of tens. Why not, then, continue the next letters as numbering groups of tens?
In other words J = ten, K twenty, L = thirty, M = forty, N = fifty, 0 = sixty, P seventy, Q = eighty, R = ninety. Then we can go on to number groups of hundreds:
S one hundred, T = two hundred, U = three hundred,
V four hundred, W = five hundred, X = six hundred,
Y seven hundred, Z = eight hundred. It would be con venient to go on to nine hundred, but we have run out of letters. However, in old-fashioned alphabets the amper sand ( amp;) was sometimes placed at the end of the alphabet, so we can say that amp; = nine hundred.
The first nine letters, in other words, represent the units from one to nine, the second nine letters represent the tens groups from one to nine, the third nine letters represent the hundreds groups from one to nine. (The Greek alpha bet, in classic times, had only twenty-four letters where twenty-seven are needed, so the Greeks made use of three archaic letters to fill out the list.)
This system possesses its advantages and disadvantages over the Babylonian system. One advantage is that any number under a thousand can be given in three symbols.
For instance, by the system I have just set up with our alphabet, six hundred seventy-five is XPE, while eight hun dred sixteen is ZJF.
One disadvantage of the Greek system, however, is that the significance of twenty-seven different symbols must be carefully memorized for the use of numbers to a thousand, whereas in the Babylonian system only three different sym bols must be memorized.
Furthermore, the Greek system cofnes to a natural end when the letters of the alphabet are used up. Nine hun dred ninety-nine ( amp;RI) is the largest number that can be written without introducing special markings to indicate that a particular symbol indicates groups of thousands, tens of thousands, and so on. I will get back to this later.
A rather subtle disadvantage of the Greek system was that the same symbols were used for numbers and words so that the mind could be easily distracted. For instance, the Jews of Graeco-Roman times adopted the Greek sys tem of representing numbers but, of course, used the He brew alphabet-and promptly ran into a difficulty. The number "fifteen" would naturally be written as "ten-five."
In the Hebrew alphabet, however, "ten-five" represents a short version of the ineffable name of the Lord, and the Jews, uneasy at the sacrilege, allowed "fifteen" to be repre sented as "nine-six" instead.
Worse yet, words in the Greek-Hebrew system look like numbers. For instance, to use our own alphabet, WRA is "five hundred ninety-one." In the alphabet system it doesn't usually matter in which order we place the symbols though, as we shall see, this came to be untrue for the Roman numerals, which are alphabetic, and WAR also means "five hundred ninety-one." (After all, we can say "five hundred one-and-ninty" if we wish.) Consequently, it is easy to be lieve that there is something warlike, martial, and of omi nous import in the number "five hundred ninety-one."