Page 20 - Math Skill - 4

18 Maths

Rules for Forming Roman Numerals
Rule 1: Repetition of a Roman numeral means addition.

For example, XXX = 10 + 10 + 10 = 30, Fact-o-meter

III = 1 + 1 + 1 = 3, XX = 10 + 10 = 20 � X can be subtracted
from L and C only.
The symbol V, L and D are never repeated. � C can be subtracted
A symbol can be repeated up to a maximum of from D and M only.
three times only.

Rule 2: A smaller numeral written to the right of a larger numeral is always added to the
larger numeral.
For example, XII = 10 + 1 + 1 = 12, XV = 10 + 5 = 15, LX = 50 + 10 = 60

Rule 3: A smaller numeral written to the left of a larger numeral is always subtracted from
the larger numeral.
For example, IX = 10 – 1 = 9, XL = 50 – 10 = 40, XC = 100 – 10 = 90

Rule 4: When a smaller numeral is placed between two larger numerals, then it is always
subtracted from the larger numeral immediately following it.
For example, XXIV = 10 + 10 + (5 – 1) = 24, XIX = 10 + (10 – 1) = 10 + 9 = 19

Exercise 1.8

1. Write the Hindu-Arabic numerals for the following Roman numerals.
(a) XXI (b) XXXVII (c) IX (d) XC

(e) XXXVI (f) LXXXI (g) XXIV (h) XCIV
2. Write Roman numerals for the following Hindu-Arabic numerals.

(a) 4 (b) 17 (c) 29 (d) 36
(e) 25 (f) 54 (g) 84 (h) 99

3. Put symbols >, < and = in appropriate boxes.

(a) XV XIV (b) V IV

(c) XIX XXI (d) IX IX

(e) XXX XXVIII (f) XXXIX XXXVII

4. Which of the following are wrong numbers? Encircle them.
XV , IXXX , VX , XIXX , XXXI

5. Write the answers in Roman numbers.
(a) 5 × 6 (b) 8 × 9 (c) 60 + 30

(d) 780 ÷ 10 (e) 80 – 35 (f) 16 + 5 + 3