Roman Numerals are A system of dating which is found on most books before 1800 and a great many after 1800. Each numeral has to be added mentally to arrive at the total. Here is the formula for the Roman Numeral numbering system.

**m=1000**

**d=500**

**c=100**

**l=50**

**x=10**

**ix=9**

**viii=8**

**vii=7**

**vii=6**

**vi=5**

**iv=4**

**iii=3**

**ii=2**

**i=1**

Some Examples:

**x= 10**

**xx=20**

**xxx=30**

**xxxi = 31**

**xxxvi = 36**

**mcccclxxxiv = 1484**

**mdxxxxv = 1545**

**mdcxlviii= 1648 **

**(the x before the l has to be subtracted)**

**mdcclxxx = 1780**

**mdcccxiii= 1813**

Another way to explain this is as follows: A numeral is a symbol used to represent a number. Each letter used in Roman numerals stands for a different number. A row of letters means that they should be added together. For example, XXX = 10 + 10 + 10 = 30, and LXI = 50 + 10 + 1 = 61. If a smaller value is placed before a larger one, you must subtract instead of adding. For example, IV= 4 (i.e., one subtracted from five). These rules will be handy in writing Roman numerals. Just convert one digit at a time. Here is an exercise to try: convert 963 to Roman numerals. 963 = 900 + 60 + 3 = CM + LX + III.

There are a few rules in converting Roman numerals to Arabic numbers. They are:

- Subtract only powers of ten, such as I, X, or C.

Writing VL for 45 is not allowed: write XLV instead.

- Subtract only a single letter from a single numeral.
- Don’t subtract a letter from another letter more than ten times greater.

This means that you can only subtract I from V or X, and X from L or C.