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Roman Numerals
Roman Numbers
Roman numerals are a system of numerical notation used in ancient Rome and still in limited use today. In this system, different letters represent different values, and the numbers are created by adding or subtracting these values.
Symbols and their values:
The Roman numerals use seven different letters that represent specific values as shown below:
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Numbers
Roman Number Rules
1. The Roman numerals are formed by combining different symbols together. The value of a Roman numeral is the sum of the values of its individual symbols.
2. A smaller symbol can be placed before a larger one to represent subtraction. For example, IV represents 4, which is one less than 5 (V - I = 5 - 1 = 4).
3. A symbol can be repeated up to three times in a row to represent its value. However, four of the same symbols in a row is not allowed. For example, III represents 3, but IIII is not correct.
4. Larger numerals cannot precede smaller numerals to represent subtraction. For example, XC represents 90, but CX is not correct.
5. Roman numerals are read from left to right, with the symbols in decreasing order of value.
For example :
When we read IV, we start from the left and move towards the right. The first symbol we encounter is I, which represents the value of 1.
The second symbol is V, which represents the value of 5. However, because V comes after I, we know that we need to subtract I from V to get the value of IV. So, IV represents the number 4, and we read it by starting from the left and moving towards the right, with the symbols in decreasing order of value. -
Roman Numerals
Writing Roman Numerals
Example 1 : Write the following numbers in roman numerals:
(a) 245 (b) 313 (c) 289
(a) 245
245 = 200 + (50 - 10) + 5 = CCXLV
(b) 313
313 = 300 + 10 + 3 = CCCXIII
(c) 289
289 = 200 + 800 + (10 - 1)
289 = CCLXXXIX
Example 2 : Write the following roman numerals in Hindu-arabic numbers:
(a) CCLVI (b) CCCXVIII (c) CLXXXIX (d) CCXXXVIII (e) CXCIV
(a) CCLVI
CCLVI = 200 + 50 + 5 + 1 = 256
(b) CCCXVIII
CCCXVIII = 300 + 10 + 5 + 3 = 318
(c) CLXXXIX
CLXXXIX = 100 + 50 + 30 + 9 = 189
(d) CCXXXVIII
CCXXXVIII = 200 + 30 + 8 = 238
(e) CXCIV
CXCIV = 100 + (100 - 90) + 4 = 194
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Roman Numerals
Writing Roman Numerals
Example 1 : Write the following numbers in roman numerals:
(a) 245 (b) 313 (c) 289
(a) 245
245 = 200 + (50 - 10) + 5 = CCXLV
(b) 313
313 = 300 + 10 + 3 = CCCXIII
(c) 289
289 = 200 + 800 + (10 - 1)
289 = CCLXXXIX
Example 2 : Write the following roman numerals in Hindu-arabic numbers:
(a) CCLVI (b) CCCXVIII (c) CLXXXIX (d) CCXXXVIII (e) CXCIV
(a) CCLVI
CCLVI = 200 + 50 + 5 + 1 = 256
(b) CCCXVIII
CCCXVIII = 300 + 10 + 5 + 3 = 318
(c) CLXXXIX
CLXXXIX = 100 + 50 + 30 + 9 = 189
(d) CCXXXVIII
CCXXXVIII = 200 + 30 + 8 = 238
(e) CXCIV
CXCIV = 100 + (100 - 90) + 4 = 194