Table for Roman Numerals
Roman Numerals  I  V  X  L  C  D  M 
Indo Arabic Numerals  1  5  10  50  100  500  1000 
Rules:
 If a symbol is repeated twice or thrice, the value of the numeral is obtained by adding the values of the symbol as many times as it is repeated.
Examples:
II = 1+1 = 2
III = 1+1+1 =3
XX = 10+10 = 20
Note: The symbol V is never repeated.
 To write a number in which the smallest digit always comes to the right of the greater digit, we add the values of all the digits.
Examples:
VII = 5 + 1 + 1 = 7
XI = 10 + 5 = 15
LXVI = 50 + 10 + 5 +1 = 66
 To write a number in which the smaller digit is placed before the greater digit, we subtract the value of the smaller digit from that of the greater digit.
Examples:
IV = 5  1 = 4
LIX = 50 + (101) = 59
Note: The symbol V is never subtrated.
 For the number beyond 10, we first write the number in groups of 10s and Is and then form the Roman numeral corresponding to the given number.
Examples:
12 = 10+2 = XII
20 = 10+10 = X+X = XX
24 = 10+10+4 = 10+10+(51) = X+X+IV = XXIV
26 = 10+10+6 = XXVI
39 = 10+10+10+9 = XXXIX
Rules for subtracting letters:
 Subtract only powers of ten, such as I, X, or C but not V or L.
Writing VL for 45 is not allowed: instead write XLV.
For 95, do not write VC(1005) instead write XCV (XC+V or 90+5.
 Subtract only a single letter from a single numeral.
Write VIII for 8, not IIX; 19 is XIX, not IXX, XIII for 13 not IIXV(1511)
 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, so MIM is not correct.
For 99, do not write IC(C1 or 1001) instead write: XCIX (XC+IX) or 90+9.
Directions: Change the given Roman Numerals into Indo Arabic Numerals. Also write a table for roman numerals from 1  40.
