Sunday, 30 October 2011

CBSE Class VI ( 6th) Mathematics Chapter 1 : Knowing our Numbers -Roman Numerals System

The numbers 1,2,3,4,5,6,7,8,9, 10 etc, which we have been using  so far, are the numbers from the Hindu-Arabic numeral system . This is not the only system available. One of the early systems of writing numerals is the system of Roman numerals e.g. I, II, III, IV, V, VI, VII, VIII, IX, X etc. This system is still used in many places.
For example, we can see the use of Roman numerals in clocks; it is also used for classes in the school time table etc.



I, II, III, IV, V, VI, VII, VIII, IX, X denote 1,2,3,4,5,6,7,8,9 and 10 respectively. This is followed by XI for 11, XII for 12,... till XX for 20. Some more Roman numerals are :
IVXLCDM
1510501005001000

Hindu-Arabic numeral system and corresponding system of Roman numerals

Hindu-Arabic
numeral system
= Roman
numerals system
Hindu-Arabic
numeral system
= Roman
numerals system
1= I 10= X
2= II20= XX
3= III 30= XXX
4= IV40= XL
5= V50= L
6= IV60= LX
7= VII70= LXX
8= VIII80= LXXX
9= IX90= XC
100= C
500= D
1000= M

The rules for writing numbers in the Roman system are :

(a) If a symbol is repeated, its value is added as many times as it occurs: i.e. II is equal 2, XX is 20 and XXX is 30.
(b) A symbol is not repeated more than three times. But the symbols V, L and D are never repeated.
(c) If a symbol of smaller value is written to the right of a symbol of greater value, its value gets added to the value of greater symbol.
VI = 5 + 1 = 6, XII = 10 + 2 = 12
and LXV = 50 + 10 + 5 = 65
(d) If a symbol of smaller value is written to the left of a symbol of greater value, its value is subtracted from the value of the greater symbol.
IV = 5 – 1 = 4, IX = 10 – 1 = 9
XL= 50 – 10 = 40, XC = 100 – 10 = 90
(e) The symbols V, L and D are never written to the left of a symbol of greater value, i.e. V, L and D are never subtracted.
The symbol I can be subtracted from V and X only.
The symbol X can be subtracted from L, M and C only.

Convert Hindu-Arabic Numbers from 1 to 100 into  Roman Numbers


Hindu-Arabic
numeral system
= Roman
numerals system
1= I
2= II
3= III
4= IV
5= V
6= VI
7= VII
8= VIII
9= IX
10= X
11= XI
12= XII
13= XIII
14= XIV
15= XV
16= XVI
17= XVII
18= XVIII
19= XIX
20= XX
21= XXI
22= XXII
23= XIII
24= XXIV
25= XXV
26= XXVI
27= XXVII
28= XXVIII
29= XXIX
30= XXX
31= XXXI
32= XXXII
33= XXXIII
34= XXXIV
35= XXXV
36= XXXVI
37= XXXVI1
38= XXXVI1I
39= XXXIX
40= XL
41= XLI
42= XLII
43= XLIII
44= XLIV
45= XLV
46= XLVI
47= XLVII
48= XLVIII
49= XLIX
50= L

Hindu-Arabic
numeral system
= Roman
numerals system
51= LI
52= LII
53= LIII
54= LIV
55= LV
56= LVI
57= LVII
58= LVIII
59= LIX
60= LX
61= LXI
62= LXII
63= LXIII
64= LXIV
65= LXV
66= LXVI
67= LXVII
68= LXVIII
69= LXIX
70= LXX
71= LXXI
72= LXXII
73= LXXIII
74= LXXIV
75= LXXIV
76= LXXV
77= LXXVI
78= LXXVII
79= LXXVIII
80= LXXX
81= LXXXI
82= LXXXII
83= LXXXIII
84= LXXXIV
85= LXXXV
86= LXXXVI
87= LXXXVII
88= LXXXVIII
89= LXXXIX
90= XC
91= XCI
92= XCII
93= XCIII
94= XCIV
95= XCV
96= XCVI
97= XCVII
98= XCVIII
99= XCIX
100= C
Question : Write the Roman number for the following Hindu-Arabic numbers : 289, 490, 758, 890, 995, 1115, 1419, 1899, 2534, 909, 1001

Answer : 
Hindu-Arabic
numeral system
= Roman
numerals system
289= CCLXXXIX
490= CDXC
758= DCCLVIII
890= DCCCXC
995= CMXCV
1115= MCXV
1419= MCDXIX
1899= MDCCCXCIX
2534= MMDXXXIV
909= CMIX
1001= MI

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