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JSS1: MATHEMATICS - 1ST TERM

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  1. Whole Numbers I | Week 1
    3Topics
    |
    1 Quiz
  2. Whole Numbers II | Week 2
    1Topic
    |
    1 Quiz
  3. Counting in Base Two | Week 3
    4Topics
    |
    1 Quiz
  4. Arithmetic Operations | Week 4
    3Topics
    |
    1 Quiz
  5. Lowest Common Multiple (LCM) | Week 5
    1Topic
    |
    1 Quiz
  6. Highest Common Factor | Week 6
    1Topic
    |
    1 Quiz
  7. Fraction | Week 7
    7Topics
    |
    1 Quiz
  8. Basic Operations with Fractions I | Week 8
    3Topics
    |
    1 Quiz
  9. Basic Operations with Fractions II | Week 9
    1Topic
    |
    1 Quiz
  10. Directed Numbers | Week 10
    2Topics
    |
    1 Quiz
  11. Estimation and Approximation I | Week 11
    3Topics
    |
    1 Quiz
  12. Estimation and Approximation II | Week 12
    6Topics
    |
    1 Quiz
Lesson 2, Topic 1
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Roman Numerals

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Roman numerals are number systems that originated in ancient Rome and remained the usual way of writing numbers throughout Europe. Numbers in this system are represented by combinations of letters from Latin alphabets. 

Roman Numerals used capital letters of the alphabet for numerals as shown below;

Natural Numbers Roman Numeral 
1I
5V
10X
50L
100C
500D
1000M

Roman numerals were first used about 2,500 years ago. They are still used presently, on clock faces, chapter numbers in books, etec.

Basic Combinations:

Natural Numbers Roman Numeral 
1I
2II
3III
4IV
5V
6VI
7VII
8VIII
9IX
Natural Numbers Roman Numeral 
10X
20XX
30XXX
40XL
50L
60LX
70LXX
80LXXX
90XC
100C
200CC
300CCC
400CD
500D
600DC
700DCC
800DCCC
900CM

Forming Numbers (Rules): 

Rule 1: When a symbol appears “after a larger” (or equal) symbol it is added. 

VI=V+I=VI
6=5+1=6

LXX=L+X+X
70=50+10=10

Rule 2: When the symbol appears “before a larger” symbol it is subtracted. 

IV=VI=IV
4=51=4

IX=XI=IX
9=101=9

Roman big numbers: 

Natural Numbers Roman Numeral 
5000\( \scriptsize \bar {V} \)
10000\( \scriptsize \bar {X} \)
50000\( \scriptsize \bar {L} \)
100000\( \scriptsize \bar {D} \)
1000000\( \scriptsize \bar {M} \)

Example 1

Change these Roman numerals to ordinary numbers: 

1. CXLVI

2. CCCLXXXVII

3. DCCCIX

Solution

1. Working from the left-hand side (LHS) 

CXLVI Means 

 C   +  XL +  VI

C = 100

XL = 40

VI = 6

∴ 100 +  40 +   6  = 146

∴ CXLVI  = 146

2. CCCLXXXVII

CCC = 300

L = 50

XXX = 30

VI = 7

∴ 300 + 50 + 30 + 7

∴ CCCLXXXVII = 387

3. DCCCIX

D = 500

CCC = 300

IX =     9

∴ 500 + 300 + 9

∴ DCCCIX = 809

Example 2

Convert the following numerals to Roman Figures 

a. 39 

b. 118

c. 1584

Solution 

a. 39 =  30 + 9 = 39 

30 = XXX, 9 = IX

     XXX +  IX = XXXIX

39 = XXXIX 

b. 118 = 100 + 10 + 8 

    C   +  X  +  VIII

118 = CXVIII

c. 1584 = 1000 + 500 + 80   +   4 

1000 = M, 500 = D, 80 = LXXX, 4 = IV

    = M   +    D  +   LXXX  + IV

1584  =  MDLXXXIV

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