Roman NumeralsRoman Numerals

A Brief History of Roman A Brief History of Roman NumeralsNumerals

Roman numerals originated in ancient Rome. Roman numerals originated in ancient Rome. This ancient counting system is believed to This ancient counting system is believed to have started with the ancient Etruscans. have started with the ancient Etruscans.

The symbol for The symbol for oneone in the roman numeral in the roman numeral system probably represented a single tally system probably represented a single tally mark which people would notch into wood or mark which people would notch into wood or dirt to keep track of items or events they dirt to keep track of items or events they were counting. It would also be easy to write were counting. It would also be easy to write on a wax tablet.on a wax tablet.

How to convert Arabic How to convert Arabic numbers to Roman Numeralsnumbers to Roman Numerals

Roman numerals are written as Roman numerals are written as combinations of combinations of seven lettersseven letters. .

I = 1 V = 5 X = 10 L = 50 I = 1 V = 5 X = 10 L = 50

C = 100 D =500 M = 1000 C = 100 D =500 M = 1000 The letters can be written as capital (XVI) The letters can be written as capital (XVI)

or lower-case letters (xvi). or lower-case letters (xvi).

   

As a general guideAs a general guide

Roman Numerals are made up by adding Roman Numerals are made up by adding or subtracting numbers like this:- or subtracting numbers like this:-

11=10+111=10+1 = XI = XI 9 = 10 – 19 = 10 – 1 = IX = IX 40 = 50 –1040 = 50 –10 == XLXL If you want to say If you want to say 1,100 1,100 in Roman in Roman

Numerals, you would say Numerals, you would say MM for for 10001000 and and then put a then put a C C after it for after it for 100100; ; 1,100 1,100 = MC= MC

900900 =1000 – 100=1000 – 100 so so the C comes before M = CMthe C comes before M = CM

Some more examples:Some more examples: VIIIVIII = 5+3 = 8 = 5+3 = 8 XIXXIX = 10+ 9 = 19 = 10+ 9 = 19 (Remember 9 is always = IX (1 less than 10)(Remember 9 is always = IX (1 less than 10) XL XL = 50-10 = 40 = 50-10 = 40 XCXC = 100-10 = 90 = 100-10 = 90 Try these on whiteboards:Try these on whiteboards:

7 = 12 = 15 = 20 =7 = 12 = 15 = 20 =

Check your answers.Check your answers.

7 = 7 = VIIVII

12 = 12 = XIIXII

15 = 15 = XVXV

20 = 20 = XXXX

Can you convert these Can you convert these numbers to Roman Numerals? numbers to Roman Numerals?

Work in pairs, answer in the back of Work in pairs, answer in the back of

books –books – 17 = 22 = 26 = 29 = 30 = 17 = 22 = 26 = 29 = 30 =

32 = 35 = 50 = so 40 =32 = 35 = 50 = so 40 =

44 = 49 = 58 = 60 =44 = 49 = 58 = 60 =

Were you correct?Were you correct?

17=17=XVIIXVII 22= 22=XXIIXXII 26= 26=XXVI XXVI 29= 29=XXIX XXIX

30=30=XXXXXX 32= 32=XXXII XXXII 35= 35=XXXVXXXV

50=50=L L so 40= so 40=XLXL

44=44=XLIVXLIV 49= 49=XLIX XLIX 58= 58=LVIIILVIII 60= 60=LXLX

Try these.Try these.

70 = 80 = 83 = 88 = 70 = 80 = 83 = 88 =

89 = 100 = so 90 =89 = 100 = so 90 =

120 = 150 = 200 = 120 = 150 = 200 =

300 = 500 = so 400 = 300 = 500 = so 400 =

How well did you do?How well did you do?

70 = 70 = LXXLXX 80 = 80 = LXXXLXXX 83 = 83 =LXXXIIILXXXIII 88 = 88 = LXXXV111LXXXV111 89 = 89 =LXXXIXLXXXIX 100 = 100 = CC so 90 = so 90 =XCXC

120 =120 =CXXCXX 150 = 150 =CLCL 200 = 200 = CCCC

300 = 300 = CCCCCC 500 = 500 = DD so 400 = so 400 = CDCD

Some more large numbers to Some more large numbers to try.try.

600 = 700 = 800 = 600 = 700 = 800 =

1000 = so 900 = 1000 = so 900 =

1600 = 1700 = 1900 =1600 = 1700 = 1900 =

2000 =2000 =

Check your answers.Check your answers.

600 = 600 = DCDC 700 = 700 = DCCDCC 800 = 800 = DCCCDCCC

1000 = 1000 = MM so 900 = so 900 = CMCM

1600 =1600 =MDC MDC 1700 = 1700 =MDCCMDCC

1900 = 1900 = MCM MCM 2000 = 2000 =MMMM

Last one.Last one.

Can you convert 2010?Can you convert 2010? MMXMMX

Now try to write today’s date.Now try to write today’s date.

Day / Month / YearDay / Month / Year

Well done. You are a Roman Numeral Well done. You are a Roman Numeral Converter!Converter!