The main differences between Roman and Hindu-Arabic numerals are that the Romans did not have a symbol for zero, and the placement of numerals within a number can sometimes indicate subtraction rather than addition. In the Hindu-Arabic number system, each digit in a number has a place value. Take a quick look at what Roman and Hindu-Arabic numerals look like:
Roman Numerals | |
I = 1 |
C = 100 |
V = 5 |
D = 500 |
X = 10 |
M = 1000 |
L = 50 |
|
Roman Numerals 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 |
XXX |
400 |
CD |
5 |
V |
18 |
XVIII |
31 |
XXXI |
500 |
D |
6 |
VI |
19 |
XIX |
40 |
XL |
600 |
DC |
7 |
VII |
20 |
XX |
50 |
L |
700 |
DCC |
8 |
VIII |
21 |
XXI |
60 |
LX |
800 |
DCCC |
9 |
IX |
22 |
XXII |
70 |
LXX |
900 |
CM |
10 |
X |
23 |
XXIII |
80 |
LXXX |
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 |
Hindu-Arabic Numerals | |||||||||
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
Example:
Placing I in front of the V, or placing any smaller number in front of any larger number, indicates subtraction. So IV means to subtract I from V, which leaves 4, and IX means to subtract I from X, which leaves 9.
Placing I after the V means addition, so VI means 6, VII means 7, VIII means 8.
Roman numerals can be changed into Hindu-Arabic numbers by taking the place value columns (highest lowest) of the Hindu-Arabic number and gradually building up the Roman numeral.
Example:
The Roman numeral for 2 305 is MMCCCV.
Example:
99 = 90 + 9
or XC + IX XCIX
So, XCIX is the Roman numeral for 99.
(Note: It is usually not represented by IC.)