How to understand Roman numbers

Roman numbers are a thing of the past but you may still run across them, occasionally. Sometimes you encounter a Roman number in a book, on a building, or even while watching the Super Bowl. It is very easy to convert a Roman number to a “normal” number, though, most people do not know how to do that. Follow these V steps and you’ll soon be able to make sense out of any Roman number you encounter.

Instructions

Difficulty: Easy

Things You’ll Need:

• The ability to add.
• The ability to subtract.
• The ability to remember a seven-word sentence.

1. Roman numerals consist of seven letters. The sequence of these letters determines the value of the Roman numeral. For example, VII = 7 and LVI = 56.
2. Memory Tip Use the following mnemonic to learn the sequence (from smallest to largest) of Roman numerals: In Very eXtreme Locations Camels Drink More.
3. There is a certain logic to Roman numerals which you can apply to convert the Roman numeral to an Arabic numeral.
4. Application 1 Application 1. When all the letters in the Roman numeral appear in DESCENDING order (use the mnemonic to determine this), then just add the value of the Roman numerals together to determine the complete value of the number. For example, LXXV = 75 and LXI = 61.
5. Application 2 Application 2. In a sequence of Roman numerals, when you see that a lower letter comes before a higher Roman letter, then subtract the value of the lower letter from the value of the higher letter. Then, as you work from left-to-right, continue to add the values of the letters together to determine the complete value of the Roman numeral. For example, LXXIV = 74 (I comes before V so, subtract 1 from 5) and MCDXLIV = 1,444 (C appears before D so, subtract 100 from 500 to get 400; X appears before L so, subtract 10 from 50 to get 40; and I appears before V so, subtract 1 from 5 to get 4).

Tips & Warnings

• Roman numerals have the same value whether they appear in upper or lower case letters. For example, XVII = xvii.
• Be thankful the Western world converted to Arabic numerals before you had to take Algebra (X = what?).