Class 6 Maths Knowing Our Numbers Roman Numerals

Roman Numerals

The number system invented by Romans is called Roman number system or Roman Numerals.

 Symbol Value Repitition Allowed I 1 Yes (3 times at max) V 5 No X 10 Yes (3 times at max) L 50 No C 100 Yes (3 times at max) D 500 No M 1000 Yes (3 times at max)

Rules for writing Roman Numerals:

1. If a symbol is repeated, its value is added as many times as it occurs. Examples,
1. II = 2
2. CCC = 300
2. A symbol is not repeated more than three times. But the symbols V, L and D are never repeated. Example,
1. XX is correct but DD is not.
3. If a symbol of smaller value is written to the right of a symbol of greater value, its value gets added to the value of greater symbol. Example,
1. XI = 11
2. VII = 7
4. If a symbol of smaller value is written to the left of a symbol of greater value, its value is subtracted from the value of the greater symbol. Example,
1. IX = 9
2. XC = 90
5. The symbols V, L and D are never written to the left of a symbol of greater value, i.e. V, L and D are never subtracted. The symbol I can be subtracted from V and X only. The symbol X can be subtracted from L, M and C only.
 Problem: Write in Roman Numerals. Solution: (a) 73 73 = 70 + 3 70 = 50 + 10 + 10 = LXX 3 = 1 + 1 + 1 = III Hence 73 can be written as LXXIII (b) 92 92 = 90 + 2 90 = 100 - 10 = XC 2 = 1 + 1 = II Hence 92 can be written as XCII

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