✌Roman numerals✌

Roman numeral system is one of the systems in which certain symbols are used to represent numbers. The system of Roman numeration is among the oldest systems developed by Romans. There are seven basic Roman numerals(symbols):

NOTE-

(a) We also use K for 1000.

(b)In the Roman system, there is no symbol for zero.

(c)This system is also not a place value system.

Basic rule to form Roman Numerals

@ Rule 1: If a symbol is repeated at the most 3 times, its value is added as many times as it occurs,

e.g., II = 1 + 1 = 2,

XX = 10 + 10 = 20,

XXX =10 + 10 + 10 = 30 , etc.

NOTE –

(a) Only I, X, C and M can be repeated. Example- II = 1 + 1 = 2 etc.

(b) V, L and D are never repeated. Example- 10 = X but 10 ≠ VV etc.

(c)No symbols can be repeated more than three times.

@ Rule 2: A smaller number written to the right of a larger number is always added to the larger numeral,

e.g., VI = 5 + 1 = 6

XI = 10 + 1 = 11

LX = 50 + 10 = 60

LXX = 50 + 10 + 10 = 70

@ Rule 3: A smaller number written to the left of a larger number is always subtracted from the larger numeral,

e.g., IV = 5 – 1 = 4

IX = 10 – 1 = 9

XL = 50 – 10 = 40

XC = 100 – 10 = 90

NOTE-

(a) V, L and D are never written to the left of a larger Roman numeral, i.e., V , L and D are never subtracted, e.g., 5 = V but 5 ≠ VX etc.

(b) I can be subtracted from V and X only, e.g., IV = 5 – 1 = 4 ; IX = 10 – 1 = 9 etc.

(c) X can be subtracted from L and C only, e.g., XL = 50 – 10 = 40 ; XC = 100 – 10 = 90 etc.

(d)C can be subtracted from D and M only, e.g., CD = 500 – 100 = 400 ; CM = 1000 – 100 = 900 etc.

@ Rule 4: When a smaller Roman numeral is placed between two larger Roman numerals, then it is subtracted from the larger Roman numeral immediately following it.

e.g., XIV = 10 + ( 5 ─ 1 ) = 10 + 4 = 14

XIX = 10 + (10 ─ 1) = 10 + 9 = 19

@ Rule 5: If a bar is placed over a Roman numeral, it is multiplied by 1000.

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e.g., V = 5000 and X = 10000, etc