Maths

Roman Numerals: Fun Facts, Charts, and Conversion Rules!

roman numerals

Quick Definition:

“Roman numerals are ancient numeric symbols that were invented by Romans. This numerical system is still here with us and is being used for many purposes, such as, denoting classrooms (i.e., class-II), book-chapters, numbers on clock, etc.” 


After going through our precise post, you will know Roman numerals completely. So let’s dig deeper into more details…  

In-Depth Definition

The Roman numeral system is enriched with different symbols, each representing one number. The number 1 is represented by I, 2 by II, 3 by III, 4 by IV, 5 by V, 6 by VI, 7 by VII, 8 by VIII, 9 by IX, and 10 by X. After the number 10, “X” is added to each roman number to convert the symbols into next numbers, such as 11 (XI), 12 (XII), 13 (XII)... 20 (XX). Further, for the series of “20” double “X” is added to the I, II, III…X.

No new symbols are used. Instead, the existing symbols are used for making new numerals, except for larger numbers, like, 500, 1000, etc. The symbols used for larger numbers are; L, C, D, and M, representing 50, 100, 500, and 1000 respectively. 

History

The numerical system was invented out of the traditional finger-counting system. Historians also claim that Roman numerals emerged during 800-900 BC. The Romans mimicked the fingers’ shapes to make the symbols “I,” “V,” and “X”. Where “V” was adopted from the shape that a thumb and finger formed, and double “X” meant two hands.

Moreover, in the initial stages, the roman numeral system was only used for verbal communications, but over time people started writing it on cave-wall, stones, etc., for calculations.

Fun Facts!

⇒ This system uses ONLY seven symbols for creating numbers!
⇒ You won’t find a single “zero” in the roman numeral system.
⇒ Romans tend to use these symbols to denote the days of the week.
⇒ Numerous renowned leaders, such as King Henry 1, Queen Elizabeth II, etc., were named after these interesting symbols.


Roman-Numeral Chart (1-50)


No.

Roman Symbol

No.

Roman Symbol

No.

Roman Symbol

No.

Roman Symbol

No.

Roman Symbol

1

I

11

XI

21

XXI

31

XXXI

41

XLI

2

II

12

XII

22

XXII

32

XXXII

42

XLII

3

III

13

XIII

23

XXIII

33

XXXIII

43

XLIII

4

IV

14

XIV

24

XXIV

34

XXXIV

44

XLIV

5

V

15

XV

25

XXV

35

XXXV

45

XLV

6

VI

16

XVI

26

XXVI

36

XXXVI

46

XLVI

7

VII

17

XVII

27

XXVII

37

XXXVII

47

XLVII

8

VIII

18

XVIII

28

XXVIII

38

XXXVIII

48

XLVIII

9

IX

19

XIX

29

XXIX

39

XXXIX

49

XLIX

10

X

20

XX

30

XXX

40

XL

50

L


Roman-Numeral Chart (51-100)


No.

Roman Symbol

No.

Roman Symbol

No.

Roman Symbol

No.

Roman Symbol

No.

Roman Symbol

51

LI

61

LXI

71

LXXI

81

LXXXI

91

XCI

52

LII

62

LXII

72

LXXII

82

LXXXII

92

XCII

53

LIII

63

LXIII

73

LXXIII

83

LXXXIII

93

XCIII

54

LIV

64

LXIV

74

LXXIV

84

LXXXIV

94

XCIV

55

LV

65

LXV

75

LXXV

85

LXXXV

95

XCV

56

LVI

66

LXVI

76

LXXVI

86

LXXXVI

96

XCVI

57

LVII

67

LXVII

77

LXXVII

87

LXXXVII

97

XCVII

58

LVIII

68

LXVIII

78

LXXVIII

88

LXXXVIII

98

XCVIII

59

LIX

69

LXIX

79

LXXIX

89

LXXXIX

99

XCIX

60

LX

70

LXX

80

LXXX

90

XC

100

C


Roman Numeral Chart (Large Numbers)


No.

Roman Numerals 

100

C

200

CC

300

CCC

400

CD

500

D

600

DC

700

DCC

800

DCCC

900

CM

1000

M


Additive Numeral Theory 

There is something magical about the Roman numeral system! You can add the symbols of one numeral number to each other and figure out what digit that Roman numeral denotes. Here are some examples for your clarification:
VIII (8) = (5+1+1+1) = 8
VI (6) = (5+1) = 6

Note: This theory can only be used if a greater value symbol appears at the start of the Roman number. For the numbers that begin with smaller value symbols, the formula discussed below should be used…

Subtractive Numeral Theory 

If a roman numeral starts with a smaller value symbol and is followed by one or more higher-value symbols, you can subtract the low values from the greater value symbol to see which digit that numeral denotes. Such as;
IV (4) = 5-1 = 4

Rules for Writing Numeral Numbers

Certain rules should be followed when playing with roman numerals. A few of the important ones are listed below:
  • One symbol can only be repeated three times or less for writing one Roman numeral.
  • The symbols V, D, and L only occur once and are never repeated (in one numeral).
  • In case the number starts with a greater-value symbol and ends with smaller-value symbols, then all the values can be added to each other for finding out which digit the Roman numeral denotes, like, VII (5+1+1)= 7.
  • If the smaller value is written first and is followed by smaller values, then the first value will be subtracted from the second value, such as IX = 10-1 = 9.
  • The symbols, V, D, and L always appear before greater values. Hence, they can not be subtracted.
  • As the symbol X denotes the digit 10, therefore, it can only be subtracted from the high-value symbols, that are, M, C, and L.
  • The symbol I can only be subtracted from X and V.
As now you know what numerical symbols are and how you can convert them into different digits, so let’s have a look at some sample questions….

Hardest Roman Conversions

⇒ Convert XXV into the number digit.

Solution: XX=20, V=5

As “XXV” starts with a greater value number, hence, the theory of addition will be applied. 

Thus, XX+V= 20+5= 25.

The number XXV denotes the digit “25”. 

⇒ Convert XC into the number digit.

Solution: X=10, C=100

As “XC” starts with a smaller value number, hence, the theory of subtraction will be applied.

Thus, C-X= 100-10= 90.

The number XC denotes the digit “90”. 

⇒ Convert XXIX into the number digit.

Solution: X=10, X=10, I=1, and X=10

As “XC” starts with a greater value symbol, the theory of addition will be applied to convert the Roman numeral into a digit. However, this Roman numeral has two separate parts, that are; XX and IX. The theory of addition will be used for the first part, and the theory of subtraction for the second part (as the second part starts with a smaller value symbol).

Thus, X+X (XI)= 10 + 10 + (10 - 1) = 29

The number XC denotes the digit “29”. 

⇒ Convert XXIV into the number digit. 

Solution: X=10, X=10, I=1, and V=5

As “XXIV” starts with a greater value symbol, hence, the theory of addition will be applied to convert the Roman numeral into the digit. However, this Roman numeral has two separate parts, that are; XX and IV. Hence, the theory of addition will be used for the first part and the theory of subtraction for the second part (as the second part starts with a small value symbol).

Thus, X+X+ (V-1) = 10 + 10 + (5 - 1) = 24

The number XXIV denotes the digit “24”. 

⇒ Convert XVII into the number digit. 

Solution: X=10, V=5, I=1, I=1

As “XVII” starts with a greater value symbol, hence, the theory of addition will be applied.

Thus, X+V+I+I= 17.

The number XC denotes the digit “17”.

⇒ Convert XXXIX into the number digit.

Solution: X=10, X=10, X=10, I=1, X=10

As “XXXIX” starts with a greater value symbol, hence, the theory of addition will be applied to convert the Roman numeral into the digit. However, this Roman numeral has two separate parts, that are; XXX and IX. Thus, the theory of addition will be used for solving the first part, and the theory of subtraction for the second part (as the second part starts with a small value symbol).

Thus, X+X+X+ (X-I) = 10+10+10+(10-1)= 39

The number XXXIX denotes the digit “39”. 

⇒ Write 61 in Roman numerals.

Solution: 61 = 60 + 1

= (50 + 10) + (10 – 9)

= LX + I

= LXI

Thus, 61 = LXIX.

⇒ Convert 1761 to Roman Numerals.

Solution:

Step 1: Break 1761 into 1000, 600, 60, 1

Step 2: Convert into Roman Numerals 

1000 = M

600 = DC

60 = LX

1 = I

1000+600a+60+1= MDCLXI

⇒ Compute the following roman numeral MCXXII – LXX – LII.

Solution: MCXXII = 1122, LXX = 70, LII = 52

MCXXII-LXX-LII= 1122 – 70 – 52 = 1000

Hence, 1000 in numeral number is MC

FAQs

Why Do We Use “k” for Thousand?

That’s because the word “k” derives from the Greek word “kilo.” Kilo means 1000 and this is why “k” is used for denoting 1000 in Roman numerals. 

When Do We Use Roman Numerals in Chemistry?

In chemistry, these symbols are used for naming ionic compounds that have more than one (possible) positive cations. Further, numeral numbers are not placed on all the compound names. 

Why do We Have Roman Numerals in the Periodic Table? 

In the periodic table, the Roman numeral denotes the oxidization state of the metal ions, plus, the charge of the same metal. 

Which is the Biggest Number in Roman Numerals?

3999 is the highest number in Roman numerals. 

Are there Negative Roman Numerals?

No! The Roman numeral system has no symbol for negative numbers and not even for the digit zero. 

In a Nut Shell!

Whether you’re learning Roman numerals for scoring good scores in your exam or for increasing knowledge, make sure to keep all the points and rules (discussed above) in front of your mind while playing with Roman numerals.

This system is one of the evergreen inventions that Romans have left for us. It’s easy to learn, plus, it’s easy to convert into today’s standard numerical digits. However, Roman numerals have no substitute for zero and negative digits. This makes sense why Roman numerals aren’t used as standard arithmetic symbols in this modern age. But, still, these ancient symbols are being used for many purposes.

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