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 :
(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.
Question : Write the Roman number for the following Hindu-Arabic numbers : 289, 490, 758, 890, 995, 1115, 1419, 1899, 2534, 909, 1001
Answer :
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 :
| I | V | X | L | C | D | M |
| 1 | 5 | 10 | 50 | 100 | 500 | 1000 |
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 | = | II | 20 | = | XX |
| 3 | = | III | 30 | = | XXX |
| 4 | = | IV | 40 | = | XL |
| 5 | = | V | 50 | = | L |
| 6 | = | IV | 60 | = | LX |
| 7 | = | VII | 70 | = | LXX |
| 8 | = | VIII | 80 | = | LXXX |
| 9 | = | IX | 90 | = | 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
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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 |
