Page 19 - Maths Class 06

VII = + + =5 1 1 7
XV = 10 + 5 = 15
LXVI = 50 + 10 + + =5 1 66

Rule 3. When a symbol is written on the left of one of the greater value, we subtract its value from value
of the symbol on its right.

For example, IV = - =5 1 4
IX = 10 - =1 9

XL = 50 10 = 40
-
XC = 100 10 = 90
-
MCM = 1900

Caution : The symbols V, L, D are never subtracted.
The symbol I can be subtracted only from V and X.

The symbol X can be subtracted only from L and C.
The symbol C can be subtracted only from D and M.
Rule 4. When a symbol of smaller value is placed between two symbols of greater values the value is
subtracted from the greater one on its right.
For example, XIV = 10 + 5 1( - ) = 14

XXIX = 10 + 10 + 10 1( - ) = 29
Rule 5. For writing numerals for numbers beyond ten, we first write the given number in for example,

For example, 12 = 10 + 2 = XII
26 = 10 + 10 + 6 = XXVI
20 = 10 + 10 = XX

39 = 10 + 10 + 10 + 9 = XXXIX
Let us consider some examples:

EXAM PLE 1. Write the follow ing Roman numer als as Hindu-Arabic numer als:
(a) LXIII (b) DCCXLVI
SOLU TION : (a) LXIII = 50 + 10 + 3 = 63
(b) DCCXLVI = 500 + 100 + 100 + 50 10( - ) + + =5 1 746

EXAM PLE 2. Write the Roman numeral for each of the follow ing:
(a) 98 (b) 587 (c) 964

-
SOLU TION : (a) 98 = 90 + 8 =(100 10 ) + +5 3 = XCVIII
(b) 587 = 500 + 50 + 10 + 10 + 10 + +5 2 = DLXXXVII
(c) 964 = 900 + 50 + 10 + 4 = CMLXIV
EXAM PLE 3. Compare the follow ing, using >, <, = :
(a) LX, XL (b) LVIII, C

SOLU TION : (a) LX > XL (b) LVIII < C

19