Page 25 - ICSE Math 5
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Rule 5: If a bar is placed over a symbol, then its value gets multiplied by 1,000.
Examples:
V = 5 × 1,000 = 5,000 L = 50 × 1,000 = 50,000
C = 100 × 1,000 = 1,00,000 D = 500 × 1,000 = 5,00,000
M = 1,000 × 1,000 = 10,00,000
Roman Numerals up to Hundred
1 2 3 4 5 6 7 8 9 10
I II III IV V VI VII VIII IX X
11 12 13 14 15 16 17 18 19 20
XI XII XIII XIV XV XVI XVII XVIII XIX XX
21 22 23 24 25 26 27 28 29 30
XXI XXII XXIII XXIV XXV XXVI XXVII XXVIII XXIX XXX
31 32 33 34 35 36 37 38 39 40
XXXI XXXII XXXIII XXXIV XXXV XXXVI XXXVII XXXVIII XXXIX XL
41 42 43 44 45 46 47 48 49 50
XLI XLII XLIII XLIV XLV XLVI XLVII XLVIII XLIX L
51 52 53 54 55 56 57 58 59 60
LI LII LIII LIV LV LVI LVII LVIII LIX LX
61 62 63 64 65 66 67 68 69 70
LXI LXII LXIII LXIV LXV LXVI LXVII LXVIII LXIX LXX
71 72 73 74 75 76 77 78 79 80
LXXI LXXII LXXIII LXXIV LXXV LXXVI LXXVII LXXVIII LXXIX LXXX
81 82 83 84 85 86 87 88 89 90
LXXXI LXXXII LXXXIII LXXXIV LXXXV LXXXVI LXXXVII LXXXVIII LXXXIX XC
91 92 93 94 95 96 97 98 99 100
XCI XCII XCIII XCIV XCV XCVI XCVII XCVIII XCIX C
To write numbers from 101 to 200, we add C before the Roman numbers.
Let’s write 101, 112 and 140 in Roman numbers to understand this.
We already know I = 1, XII = 12 and XL = 40.
Thus, on adding C before these Roman numbers, they will become CI, CXII and CXL, i.e., CI = 101,
CXII = 112 and CXL = 140.
Writing Roman Numerals Using Hindu-Arabic Numerals
We know that numbers 1, 2 and 3 are written as I, II and III, respectively, according to the Roman
numeral system. But 4 cannot be written as IIII since the symbol I cannot be repeated more than
three times in a row.
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