How to Read & Convert Roman Numerals

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The use of Roman numerals started way back in the first millennium, BC. Roman numerals were used to mark on stones, coins and art materials. Initially, the symbols used looked a little different than now. Over a period of time, the symbols were replaced with letters from the Roman alphabet and have stayed that way since.

How to Read and Convert Roman Numerals

Learn the basic units of Roman numerals. Use the following (Roman to Arabic) list:

  • I – 1 (One)
  • V – 5 (Five)
  • X – 10 (Ten)
  • L – 50 (Fifty)
  • C – 100 (hundred)
  • M – 1000 (Thousands)

Read the Roman numerals from left to right.

If values of individual numerals are decreasing or equal, then add them together to get the value of the whole Roman numeral. For example, XVII is equal to 10+5+1+1 = 17 and XX is equal to 10+10=20.

If values of individual numerals are increasing from left to right then subtract and get the value of the whole Roman numerals. For example, IV is equal to 5-1 = 4.

If a Roman numeral doesn’t fall under any of the above explained categories, then convert it using the first category and get the value. For example, the value of XIV can be obtained as 10+ (5-1) = 14; MLM is equal to 1000 + (1000-50) = 1950.

Very large Roman numerals are expressed by placing a bar above a smaller Roman numeral. If a bar is placed above Roman numerals then it become 1000 times large. For example, a bar placed over V is equal to 5000.

Where will you See Roman Numerals?

In most places Arabic numbers are used for their simplicity. But there are still many places where you will see Roman numerals:

  • The name of kings and popes like Charles II.
  • On some watches you can see the hour marks as Roman numerals.
  • Appendix page numbers of books are traditionally written using Roman numerals.
  • Historical events such as wars. i.e. World War II.
  • Construction dates of some buildings.
  • Sometimes used for writing film series' titles. For example, Rambo II.
  • Numbering in guitar cord diagrams.

Can you think of any other places?

In the early days, various symbols were used as Roman numerals. Due to simplicity and some added benefits (like the use of zero, fractions etc.), the Arabic number system has been adapted widely and the use of Roman numerals has been greatly limited. However, you will still see instances of Roman Numberals in your every day life. Converting numbers into Roman Numerals can be a fun brain challenge. Try doing it next time you’re on a car trip!