NUMBERS

Roman Numbers

• The Roman Numbers system is an old numeral system.
• Roman Numbers system is used throughout Europe.
• Roman numbers are represented by some letters from the Latin alphabet.
• Gradually Roman Numeral system changed to the Modern Roman Numbers system.
• In modern system seven different letters are used to represent Roman Numbers.

Each of these seven different letters represent different numerical value:

We can convert any Roman Numeral in Hindu-Arabic number, also Hindu-Arabic number can be written in the form of a Roman Numeral.

Note:

1. In Roman number system there is no symbol for zero.
2. Also, there is no place value system.

Interpretation of Roman Number

Rule 1: When one letter is present and repeated in number then the value of the symbol is added with itself.

Examples:

XXX=30

CCCC=400

Note 1: Also, the symbols V, L, D are never repeated.

Rule 2: When a letter with smaller value is present after a letter with greater value, then the value of the letter will be added.

Examples:

DXXX=530

MCC=1200

Rule 3: When a letter with smaller value is present before a letter with greater value, then subtract that small value from the greater value.

Examples:

LM=950

Rule 4: A symbol cannot be repeated more than three times. There are some Roman Numbers:

Rule 5: 1000 can be represented by a line on the letter, which is called bar.

Examples:

Rule 6: Also, the letter use in mixed form can be determine as integer.

Addition and subtraction of Roman Numbers:

Rule for addition:

Step 1: First we convert the given Roman numerals into Hindu-Arabic number.

Step 2: Then we add the Hindu-Arabic numbers.

Step 3: Now again we convert the Hindu-Arabic number (number from Step 2) into Roman Numerals.

Example:

Add LV and XV.

Solution:

Here, LV = L +V
= 50 + 5
= 55
XV = X + V
= 10 + 5
= 15
Now, LV + XV will be 55 + 15 = 70
Now, 70 = 50 + 10 + 10
= L + X + X
= LXX
Finally, we get, LV + XV = LXX.

Rule for subtraction:

Step 1: First we convert the given Roman numerals into Hindu-Arabic number.

Step 2: Then we subtract the Hindu-Arabic numbers.

Step 3: Now again we convert the Hindu-Arabic number (number from Step 2) into Roman Numerals.

Example:

Subtract XXVII from LXXXVIII.

Solution:

Here, XXVII = X + X + V + I + I
= 10 + 10 + 5 + 1 + 1
= 27
LXXXVIII = L + X + X + X + V + I + I + I
= 50 + 10 + 10 + 10 + 5 + 1 + 1+ 1
= 88
Now, LXXXVIII – XXVII will be 88 – 27 = 61
61 = 50 + 10 + 1
= L + X + I
= LXI

Use of Roman Numbers:

1. We use roman numerals in clocks and watches.
2. Roman numbers are used to signifying of book chapters.
3. Roman numbers used in National football League for title.

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