Class 6 Maths - Knowing Our Numbers (Roman Numbers) #class6Maths #RomanNumbers #eduvictors

Class 6 Maths - Knowing Our Numbers (Roman Numbers)

👉 Around the 3rd century BCE, Romans developed their own number system for counting.

👉 Roman Numerals used symbols to represent numbers such as

 Roman Numeral Hindu-Arabic Numeral

  I 1

  V 5 

  X 10

  L 50

  C 100

  D 500 

  M 1000

👉 Repetition of Roman Numerals means addition but using the following rules 

- Only I, X, C, M may be repeated  

- V, L, D are never repeated

- No symbol can be repeated more than 3 times.

e.g.  III = 1 + 1 + 1 = 3, 

  VI = 5 + 1 = 6, 

  VII = 5 + 1 + 1 = 7

  XX = 10 + 10 = 20

  XXII = 10 + 10 + 1 + 1 = 22

  CC = 100 + 100 = 200

  CX = 100 + 10  = 110

👉 Smaller numerals written to the left of a larger numeral means subtraction. 

  e.g. IV = (-1)5 = 5 -1 = 4

     XC = (-10)100 = 100 - 10 = 90

  Following rules are followed in subtraction.

  - V, L, D are never repeated.

  - I can be subtracted from V and X only

    e.g. IX = 9, IL = Not Valid

  - X can only be subtracted from L and C

    e.g. XL = (-10)50 = 50 - 10 = 40

  - C can only be subtracted from D and M only

Q1: Write each of the following Roman numerals as Hindu-Arabic numerals:

(a) II

(b) XX

(c) XV

(d) CC

(e) CD

(f) XC

Answer: 

(a) II = 1 + 1 = 2

(b) XX = 10 + 10 = 20

(c) XV = 10 + 5 = 15

(d) CC = 100 + 100 = 200

(e) CD = -100 + 500 = 500 - 100 = 400 

(f) XC = -10 + 100 = 100 - 10 = 90

Q2: Express each of the following as a Roman numeral

  (a) 8

  (b) 14

  (c) 195

  (d) 341

  (e) 99

Answer:

  (a) 8 = 5 + 1 + 1 + 1 = VIII

  (b) 14 = 10 + (-1) + 5 = XIV

  (c) 195 = 100 + 90 + 5 

  = C + XC + V = CXCV

  (d) 341 = 300 + 40 + 1 

    = 100 + 100 + 100 + 50 - 10 + 1

    = C + C + C + L - X + I

    = CCCXLI

  (e) 99 = 90 + 9 = 100 - 10 + 10 -1 

    = XC + IX = XCIX

👉See Also:

Knowing Our Numbers (NCERT Ex 1.1)
Knowing Our Numbers (NCERT Ex 1.2)
Knowing Our Numbers (NCERT Ex 1.3)
Number System (MCQs)