The Basics of Roman Numerals: Understanding XXV and XXVIII

roman numerals

What are Roman Numerals?

Roman numerals are symbols that represent numbers. The Hindu-Arabic numeric system replaced this number system, which had its roots in the antiquity of the Roman system. The letters I, V, X, L, C, D, and M stand for 1, 5, 10, 50, 100, 500, and 1,000, respectively. When two symbols are combined, they may form other numerals. The Romans created this ancient technique to assist them with counting and for other daily tasks. Roman numerals only require seven letters, and the quantity and arrangement of these letters determine the final number’s value.

History of Roman Numerals

Roman numerals are believed to have existed as early as the ninth century BC. Roman numerals may have originated as cattle-counting tally sticks used by shepherds. Similar to the tally markings that we employ today, the shepherds carved notches in their sticks in the past. A single line represented each cow; every fifth and tenth cow was drawn as V or X shapes. Romans also used these numbers in commerce when they needed to keep track of their commercial operations.

Another theory suggests that Roman numbers represented hand signals. The letter “I” signified one finger,  “II” indicated two fingers, and so on. “V” was made by joining the fingers and extending the thumb. Six through nine could be symbolized using a “V” made with one hand and a single finger with the other. They would make an “X” with their thumbs to signify the number 10. Until the late middle ages, Roman numerals were widely utilized as the accepted writing system throughout Europe. It is believed that the Romans invented them since it is difficult to count with your fingers after a number reaches 10.

One more theory is called “Hand Signals Theory.” It indicates that the Roman numbers display the hand signals for counting.

  • According to this hypothesis, the fingers used to count are equivalent to the numbers one (I), two (II), and three (III);
  • When you open one hand and extend all five fingers, a V (five) symbol appears between the thumb and fingers;
  • The numbers six (VI), seven (VII), and eight (VIII) signify a hand displaying five (V) and an additional hand showing the corresponding numbers;
  • The number 10 is formed by two hands forming the shape of an ‘X’ while showing two fives;
  • The letter L was changed in later eras to stand in for the number 50;
  • In the past, writing the number 100 typically involved placing an “I” on top of an “X,” while 500 and 1000 were denoted by a circle around a “V” and an “X,” respectively. Greek letters were changed in later eras, and ‘C’ was used for 100, ‘D’ for 500, and ‘M’ for 1000;
  • For greater values, lines (vinculum or virgule) were placed to represent multiplication by 1,000.

How to Read and Write Roman Numerals?

Roman numerals may initially appear complicated, but they are pretty simple once you learn how to read them. Here you will find information to help you understand how to read and write Roman numerals. There are various rules for how to write Roman numerals, but as soon as you know them, it will be easy for you to read them.

The following guidelines can be used to convert numbers to Roman numerals:

  1. Roman numbers are read from left to right;
  2. They are created by mixing the seven addition- and subtraction-based letters;
  3. The order of the numerals indicates whether you need to add or remove values;
  4. Do not use the same letter more than three times in a row;
  5. Adding a sign after one with an equal or higher value increases the number;
  6. By putting a sign in front of one with a higher value than it, the number gets smaller;
  7. Placing a bar above a number increases it by 1,000.

Here are a few instances of numbers written in Roman numerals:

Roman numeral representation of 4: The closest symbol to 4 is 5, which is “V.” Since 4 is one less than 5, “I” stands in for 1. When “I” is put in front of “V,” 5 is decreased by one. Thus, 4 is IV.

Turn 73 to Roman letters:  The sign closest to 73 is 50; thus, that is “L.” Since 70 is twenty more than 50 and 20 is two tens, “XX” stands in for 20. “XX” after “L” stands for 70: LXX. Therefore, three I’s would be put after the X to increase the number to 73. This makes 73 LXXIII.

Roman numeral representation of 2450: since the number 2450 is closest to 1000, we use “M.” There would need to be two M’s because it is greater than 2000. The nearest to 500 is 400. 500 is “D,” but 100 must be taken away. “C” comes before “D,” and 400 is created by removing 100 from 500. MMCD is thus 2400. Last but not least, “L” stands for 50. Thus, MMCDL is 2450.

Common Uses of Roman Numerals

Roman numbers are employed in history and are one of the numbering systems used in modern mathematics. We may find Roman numerals:

  • On clocks and watches;
  • Roman numerals are still used for book chapter headings and numbered points in print;
  • Roman numerals are still used to refer to monarchs, queens, emperors, and popes with the same names (as in Louis XVI of France or Pope Benedict XVI), as well as in fields like chemistry, pharmaceuticals, seismology, and theology when deemed relevant;
  • Roman numerals may be employed within the film business to denote the year a film was made;
  • Roman numerals are used in sporting events like the Olympic Games and the Super Bowl to indicate how often they have been performed.


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