Roman Numeral Conversion
April 4th, 2008
To convert an Arabic number into a Roman numeral, the following Roman numeral conversion rule can be used.
To make the Roman numeral for the Arabic number 2, for example, the Roman numeral I is added to the same Roman numeral I making the Roman numeral II. Therefore, Roman numeral II is equal to the number 2.
1 = I
2 = I + I = II
3 = I + I + I = III
Roman numeral conversion rule
Example: 4 = 5 – 1 or V – I. V – I is written in Roman numeral form as IV.
As a Roman numeral conversion rule, when a letter representing a number of lesser value (I before V) appears to the left of a letter of greater value (V after I), the lesser value (I) is subtracted from the greater value (V).
Math Worksheets practice
Arabic numbers |
Roman mathematical equivalent |
Roman numerals |
| 9 | X – I (10 – 1) | IX |
| 20 | XXX – X (30 – 10) | XX |
| 40 | L – X (50 – 10) | XL |
| 90 | C – X (100 – 10) | XC |
Click here to go back to Roman numerals information page
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