Roman number system: We have been using the Hindu-Arabic numeral system so far. This is not the only system available. One of the early systems of writing numerals is the system of Roman number system. This system is still used in many places.
Roman Numeral Table
1
I
14
XIV
27
XXVII
150
CL
2
II
15
XV
28
XXVIII
200
CC
3
III
16
XVI
29
XXIX
300
CCC
4
IV
17
XVII
30
$\chi \chi\chi$
400
CD
5
V
18
XVIII
31
$\chi \chi\chi$1
500
D
6
VI
19
XIX
40
XL
600
DC
7
VII
20
XX
50
L
700
DCC
8
VIII
21
XX1
60
LX
800
DCCC
9
IX
22
XXII
70
LXX
900
CM
10
X
23
XXIII
80
L$\chi \chi\chi$
1000
M
11
XI
24
XXIV
90
XC
1600
MDC
12
XII
25
XXV
100
C
1700
MDCC
13
XIII
26
XXVI
101
CI
1900
MCM
Unlike the Hindu-Arabic Numeral System, Roman Numeral System uses 7 basic symbols to represent different numbers. The symbols are as follows :
I = 1 V =5 X= 10
L = 50 C =100 D=500 M= 1000 Rules to form Roman Numerals:
1) If symbol is repeated then its value is added.
2)The symbols I,X,C and M can be repeated maximum 3 times.
3)The symbols V,L and D can never be repeated.
4)If a symbol with smaller value is written on right of greater value then smaller value is added to the greater one.
5)If a symbol with smaller value is written on left of greater value then smaller value is subtracted from the greater one.
Example : 1) Write equivalent Roman numerals of a) 29 b) 395 c)62 Solution : a) 29---> XXIX
b)395 ---> CCCXCV
c) 62 ---> LXII
Example: 2) Write a) XLIV b)DCC in Hindu-Arabic numerals. Solution: a)XLIV ----> 44
b)DCC ----> 700
Example : 3) Add XXII + CD Solution:
XXII = 22
CD = 400
XXII + CD = 22 +400
= 422
Example : 4)Add XLIV + LIV Solution :
XLIV = 44
LIV = 54
∴ XLIV + LIV = 44 + 54
= 98
98 = XCVIII
