JSS1: MATHEMATICS  1ST TERM

Whole Numbers I  Week 13 Topics1 Quiz

Whole Numbers II  Week 21 Topic1 Quiz

Counting in Base Two  Week 34 Topics1 Quiz

Arithmetic Operations  Week 43 Topics1 Quiz

Lowest Common Multiple (LCM)  Week 52 Topics1 Quiz

Highest Common Factor  Week 61 Topic1 Quiz

Fraction  Week 77 Topics1 Quiz

Basic Operations with Fractions I  Week 83 Topics1 Quiz

Basic Operations with Fractions II  Week 91 Topic1 Quiz

Directed Numbers  Week 103 Topics1 Quiz

Estimation and Approximation I  Week 113 Topics1 Quiz

Estimation and Approximation II  Week 126 Topics1 Quiz
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Roman Numerals
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 
1  I 
5  V 
10  X 
50  L 
100  C 
500  D 
1000  M 
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 
1  I 
2  II 
3  III 
4  IV 
5  V 
6  VI 
7  VII 
8  VIII 
9  IX 
Natural Numbers  Roman Numeral 
10  X 
20  XX 
30  XXX 
40  XL 
50  L 
60  LX 
70  LXX 
80  LXXX 
90  XC 
100  C 
200  CC 
300  CCC 
400  CD 
500  D 
600  DC 
700  DCC 
800  DCCC 
900  CM 
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  =  V  –  I  =  IV 
4  =  5  –  1  =  4 
IX  =  X  –  I  =  IX 
9  =  10  –  1  =  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 lefthand 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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