By.. Miss Prangtip Kaewsuphot Roman Numeral By.. Miss Prangtip Kaewsuphot

A number system is a set of characters and mathematical rules rules that are used to represent number. Examples include the Arabic, Babylonian, Chinese, Egyptian, Greek, Mayan and Roman number systems. Roman Numerals represented the standard numbering system and method of arithmetic in ancient Rome and Europe. It was developed 2000 years ago. The system used seven letters of the alphabet to write any number. These are as follows. I = 1 X = 10 C = 100 M = 1000 V = 5 L = 50 D = 500

There is no zero in the Roman system There is no zero in the Roman system. An important difference between the decimal system and the Roman system is that the Roman system does not use place value. Study the following rules to read and write numerals in the Roman system. Rule 1 : Numerals I, X, C and M can be repeated to represent a number. Repetition of these numerals means addition. e.g. II = 2, XXX = 30, CCC = 300, MM = 2000 The symbol I, X and C can not be repeated than 3 times in a numeral, e.g. 4 is written as IV, not IIII. Symbols, V, L, D, are not repeated.

Rule 2 : A smaller numerals written to the right of a numeral of greater value is always added to greater numeral. e.g. VII = 5 + 2 = 7 XI = 10 + 1 = 11 LX = 50 + 10 = 60 MC = 1100 Rule 3 : A smaller numeral written to the left of a numeral of greater value is always added to the greater numeral. e.g. IV = 5 – 1 = 4 XC = 100 – 10 = 90 CD = 500 – 100 = 400 CM = 1000 – 100 = 900 Rule 4 : When a smaller numeral is placed between two numerals of greater value, it is always subtracted from the greater numeral immediately Following it. e.g. XXX = 10 + 10 + (10 – 1) = 29, DIX = 500 + (10 – 1) = 509

* The symbol I can be subtracted from V and X. * The symbol X can be subtracted from L and C. * The symbol C can be subtracted from D and M. * Symbols V, L, D are never subtracted. Write 3249 in Roman numerals. 3429 = 3000 + 200 + 40 + 9 = MMM + CC + XL + IX = MMMCCXLIX Write MDCLXVII in denary system. MDCLXVII = M + DC + LX + VII = 1000 + 600 + 60 + 7 = 1667

EXERCISE 1. Write the following numbers in Roman numerals. 36 (ii) 39 (iii) 506 (iv) 791 (v) 312 979 (vii) 999 (viii) 731 (ix) 2800 (x) 1347 1526 (xii) 2350 2. Write the following numbers in decimal notation. XXVII (ii) XXXIX (iii) DXC LIX (v) DCCLXXVI (vi) CMLXIX CCXVII (viii) CDIV (ix) CMLXXI (x) MXXXIV (xi) MCXI (xii) MCCXLVII

Points to remember The seven letters of the alphabet – I, X, C, M, V, L, D are used as basic symbols to write any number in Roman system of numeration. The Roman System does not have zero. 3. The Roman System does not use place value.

Story Time … The history of Roman numerals and Roman mathematics isn’t well documented. The development of the numeric symbols may have been closely related, originally, to the shape of the hand: I for a single finger, V for the whole hand outstretched, X for both hands in the same manner.