Page 24 - Math Skill - 5

22 Maths

Rule 3: A symbol for smaller number written to the left of a larger number is always
subtracted from the larger number.

For example, IV = 5 – 1 = 4, IX = 10 – 1 = 9, etc.
Rule 4: When a symbol for a smaller number is placed between symbol of two larger
numbers, then it is always subtracted from the larger number immediately following
it.
For example, XIV = 10 + (5 – 1) = 14, CXIV = 100 + 10 + (5 – 1) = 114, etc.

Fact-o-meter

� Only I, X, C, M can be repeated.
� V, L and D cannot be repeated.
� A symbol can be repeated up to a maximum number of 3 times.
� The symbols V, L and D are never subtracted.
� X can be subtracted from L and C only.
� C can be subtracted from D and M only.
� I can subtract from X and V only.

Writing Large Roman Numerals
To write a given number in Roman number system, we follow these steps:

Step 1: Write the given number in expanded form.

Step 2: Write the Roman number for the larger number.

For example, Hundreds first, then tens and then ones.
Let’s learn through examples.

Let’s Attempt

Example 1: Write the following numbers in Roman number system.

(a) 75 (b) 93 (c) 147 (d) 273 (e) 326 (f) 413
Solution: (a) 75 = 70 + 5 (b) 93 = 90 + 3 (c) 147 = 100 + 40 + 7
= LXX + V = XC + III = C + XL + VII

= LXXV = XCIII = CXLVII

(d) 273 = 200 + 70 + 3 (e) 326 = 300 + 20 + 6 (f) 413 = 400 + 10 + 3
= CC + LXX + III = CCC + XX + VI = CD + X + III

= CCLXXIII = CCCXXVI = CDXIII
Example 2: Write the Roman numbers in Hindu-Arabic number system.

(a) CIV (b) CLXVI (c) CDXXXV
Solution: (a) CIV = C + IV (b) CLXVI
= 100 + 4 = C + L + X + VI

= 104 = 100 + 50 + 10 + 6 = 166