Origin of Roman Numerals
Roman numerals started as a method of counting with fingers. “I” meant one finger. People would make I mark to show a single score mark on wood. It was also a form of a message which one person conveyed to another, with the use of fingers.
When you show five fingers, your thumb and index finger makes a “V” sign; and from here V started to mean 5. Ten ones were drawn in a straight line, and marked off with an X, and therefore X meant 10.
Thinkers like Aristotle and Archimedes needed a more sophisticated system for bigger calculations. So, the counting system was expanded. The Latin word “centum” means 100, and so “C” denoted 100. “M” came from the Latin word “mile” meaning a thousand. This system has no number zero.
Main Letters and Meaning of Roman Numerals
The main seven letters are:
I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1000
XVI = 16 (10 + 5 + 1 = 16). The letter of greater value comes before the letter of lesser value, and so you add the numbers. Also, you can add two letters at one time.
But IV = 5 – 1=4. CM= 1000 – 100= 900. Here the letter of lesser value comes before the letter of greater value, and hence we subtract the greater value from the smaller value.
Remember the Rule
The fixed rule for placing letters :
I View X Rays – I, V, X
Lucky Cows Drink Milk – L, C, D, M
The same symbol is not placed more than three times in a row. Only the power of ten is subtracted, so V and L are not subtracted. Only one number is subtracted from another. So 13 is not IIXV (15-2); but XIII (10 + 3).
Roman numerals have the disadvantage of not being conducive to adding or subtracting fractions.
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