5th Class Mathematics Roman numerals Rules for Using Symbols

Rules for Using Symbols

Category : 5th Class

*    Rules for Using Symbols

 

Rule 1: When a symbol is repeated, its value is multiplied as many times as the symbol repeated.  

 

II = 1 x 2 = 2,

III = 1 x 3 = 3,

XX = 10 x 2 = 20,

XXX = 10 x 3 = 30.

 

Note: A symbol cannot be repeated more than 3 times.

 

 

50 cannot be written as XXXXX.

Rule 2: The symbols whose value are power of 10 can be repeated. In other word the symbols, I, X, C, M can be repeated.  

 

 

XXX = 30 , MM = 2000

Rule 3: The symbols whose value are either 5 or product of 5 and a power of 10 cannot be repeated. In other words V, L, and D cannot be repeated.  

 

It is wrong to write LL for 100.

Rule 4: If a symbol of smaller value is right to the symbol of greater value, their values are added.  

 

 

VI = 5 + 1 = 6, XV = 15, LX = 50 + 10 = 60.

Rule 5: If a symbol of smaller value is left to the symbol of greater value, their difference is the resulting value.  

 

 

IV = 5 - 1 = 4, IX = 10 - 1 = 9.

Rule 6: The symbols whose value are either 5 or product of 5 and a power of 10 never subtracted. In other word V, L, and D are never written left to the symbol of greater value.        

 

 

V cannot be written immediately left to X, L, C, D, and M; L can be written immediately left to the C, D, and M; D cannot be written left to the M.

Rule 7: If a symbol of smaller value comes between two symbols of larger value, its value is subtracted from the value of the symbol which is right to it.  

 

 

XIX = 10+(10 - 1) = 19, L1V = 50 + (5 - 1).

Rule 8: A symbol of smaller value cannot be repeated two or more than two times left to a symbol of larger value.  

 

30 cannot be written as XXL, similarly 8 cannot be written as IIX.

Rule 9: When a bar (horizontal line) is placed over a Roman symbol, the value of the symbol is increased by 1000 times.

 

 

 \[\overline{\mathbf{I}}=\mathbf{1000},\text{ }\overline{\mathbf{v}}=\mathbf{5000}.\]

 

Look at the following table:  

I 1   XXI 21   XLI 41   LXI 61   LXXXI 81
II 2 XXII 22 XLII 42 LXII 62 LXXXII 82
III 3   XXIII 23   XLIII 43   LXIII 63   LXXXIII 83
IV 4   XXIV 24   XLIV 44   LXIV 64   LXXXIV 84
V 5   XXV 25   XLV 45   LXV 65   LXXXV 85
VI 6   XXVI 26   XLVI 46   LXVI 66   LXXXVI 86
VII 7   XXVII 27   XLVII 47   LXVII 67   LXXXVII 87
VIII 8   XXVII 28   XLVIII 48   LXVIII 68   LXXXVIII 88
IX 9   XXIX 29   XLVIII 49   LXIX 69   LXXXIX 89
X 10   XXX 30   XLIX 50   LXX 70   XC 90
XI 11   XXXI 31   LI 51   LXXI 71   XCI 91
XII 12   XXXII 32   LII 52   LXXII 72   XCII 92
XIII 13 XXXIII 33   LIII 53   LXXIII 73   XCIII 93
XIV 14 XXXIV 34   LIV 54   LXXIV 74   XCIV 94
XV 15 XXXV 35   LV 55   LXXV 75   XCV 95
XVI 16 XXXVI 36   LVI 56   LXXVI 76   XCVI 96
XVII 17 XXXVII 37   LVII 57   LXXVII 77   XCVII 97
XVIII 18 XXXVIII 38   LVIII 58   LXXVIII 78   XCVIII 98
XIX 19 XXXIX 39   LIX 59   LXXIX 79   XCIX 99
XX 20 XL 40   LX 60   LXXX 80   C 100
    D 500
  M 1000

 

Write the Roman numeral for 317.

Explanation

317 = 300 + 10 +7

And 300 = CCC, 10 = X, 7 = VII

Thus 317 = CCCXVII.  

 

 

Write the Roman numeral for 548.

Explanation

548 = 500 + 40 + 8 .

And 500 = D, 40 = XL(XXXX can not be written  for 40), 8 = Vlll.  

 

 

Find the value of \[\overline{\text{XIV}}.\]

 

Explanation 

XIV =24, XIV = 24000.  

 

 

Arrange the following in ascending order:

LXIX, XXIX, XLVII, CLIV, XCIX


Explanation

LXIX = 69, XXIX =29, XLVII = 47, CLIV = 154, XCIX = 99

Thus XXIX, XLVII, LXIX, XCIX, CLIV    

 

 

 

  • MDCLXVI is the smallest Roman numeral in which each of the symbols occurs.
  • MDCLXVI is the largest Roman numeral in which each of symbols occurs.  

 

 

  • I, X, L, C, D, and M are seven symbols which are used to write any Roman numeral.
  • No symbols can be repeated more than 3 times.
  • Symbols like I, X, C and M can be repeated.
  • Symbols like V, L and D cannot be repeated.
  • If a symbol of smaller value is right to the symbol of greater value, their values are added.
  • If a symbol of smaller value is left to the symbol of greater value, their difference is the resulting value.    

 

 

 

 

Which one of the following Roman numerals is correct for 745?

(a) CCCMLXV                                    

(b) DCCLXV

(c) DCCXLV                                         

(d) DMXLV

(e) None of these

 

Answer: (c)  

 

 

Amelia made a mistake while writing Roman numeral for 445. She wrote CDXIV. How will you correct themistake

(a) C should be replaced by L     

(b) I should be replaced by L

(c) I should be replaced by M     

(d) X should be replaced by C

(e) None of these  

 

Answer: (b)  

 

 

For which one of the following numbers, each Roman symbol used exactly once?

(a) 1666                                               

(b) 1999

(c) 1990                                               

(d) 1000

(e) None of these  

 

Answer: (a)  

 

 

XL represents a number. If place of the symbols is interchanged, the number will increased by:

(a) 1                                                      

(b) 5

(c) 10                                                    

(d) 20

(e) None of these  

 

Answer: (d)  

 

 

Smallest 3 digit number is subtracted from smallest 4 digit number. Write the result in Roman numeral.

(a) DM                                                 

(b) CM

(c) DCM                                               

(d) MC

(e) None of these  

 

Answer: (b)  

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