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Roman Numerals Past and Present. Romans used them for trading and commerce.When Romans learned to write they needed a way to write their numbers.Roman numerals are still used today in many different ways.There is no zero in Roman numerals.. What Are Roman Numerals? I and V . The easiest way to no
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1. Roman Numerals
2. Roman NumeralsPast and Present Romans used them for trading and commerce.
When Romans learned to write they needed a way to write their numbers.
Roman numerals are still used today in many different ways.
There is no zero in Roman numerals.
3. What Are Roman Numerals?I and V The easiest way to note down a number is to make that many marks - little I's.
So, I means 1, II means 2, III means 3.
However, four strokes seemed like too many.
So the Romans moved on to the symbol for 5 - V.
4. What Are Roman Numerals I and V Placing I in back of the V — or placing any smaller number in back of any larger number — means you should subtract.
So IV means 4. V = 5 I = 1 5 – 1 = 4
5. What Are Roman NumeralsI and V
Placing I after the V — or placing any smaller number after of any larger number — means you should add.
So, VI = 6, VII = 7, VIII = 8.
V = 5 I = 1 5 + 1 = 6
V = 5 II = 2 5 + 2 = 7
V = 5 III = 3 5 + 3 = 8
6. X means 10.
But wait — what about 9?
IX means to subtract I from X, which will = 9.
X = 10 I = 1 IX means 10 – 1 = 9 What Are Roman Numerals?X = 10
7. One 1 = I
Two 2 = II
Three 3 = III
Four 4 = IV
Five 5 = V What Are Roman Numerals?
8. Six 6 = VI
Seven 7 = VII
Eight 8 = VIII
Nine 9 = IX
Ten 10 = X
What Are Roman Numerals?
9. Eleven 11 = XI
Twelve 12 = XII
Thirteen 13 = XIII
Fourteen 14 = XIV
Fifteen 15 = XV
What Are Roman Numerals?
10. Numbers in the twenties and thirties follow the same form, only with X's indicating the number of tens.
So XXIV is 24
XXXI is 31
XXXVII is 37
What Are Roman Numerals?
11. What Are Roman Numerals?L = 50
12. C stands for centum, the Latin word for 100. A centurion led 100 men. We still use this in words like "century" and "cent.“
C = 100 What Are Roman Numerals?C = 100
13. The subtraction rule means 90 is written as XC.
Like the X's and L's, the C's are tacked on to the beginning of numbers to indicate how many hundreds there are:
CCCLXIX is 369.
14. D stands for 500.
As you can probably guess by this time, CD means 400.
So CDXLVIII is 448. What Are Roman Numerals?D = 500
15. M is 1,000. You see a lot of Ms because Roman numerals are used a lot to indicate dates.
CE (Common Era; Christians use AD for Anno Domini, "year of our Lord"). What Are Roman Numerals?M = 1000
16. Roman vs. Arabic Numerals Arabic Numerals are the numbers that we use today.
1, 2, 3, 4, 5, 6, 7, 8, 9, 0
Roman Numerals are used today, but not in everyday writing.
I, V, X, L, C, D, M
17. The Basics I = one
V = five
X = ten
L = fifty C = one hundred
D = five hundred
M = one thousand
18. The Rules for Writing Roman Numerals The letters should be arranged from largest to smallest.
1510 is written MDX, largest to smallest
19. The Rules for Writing Roman Numerals Only powers of ten can be repeated.
Don’t repeat a letter more than three times in a row.
100 is C. However, it could be written LL, NEVER XXXXXXXXXX (too many repeats)
20. Numbers are written using subtraction on the left.
A letter with a smaller value goes before one of the larger value.
The smaller number is then subtracted from the larger number.
The Rules for Writing Roman Numerals
21. Placing smaller numbers after the larger number means you should add.
So, IV means subtract the I IV = 4
VI means add the I VI = 6
IX means subtract IX = 9
XI means add XI = 11
The Rules for Writing Roman Numerals
22. The Rules for Writing Roman Numerals
33. Practice 515 = ?
1005 = ?
32 = ?
9= ?
34. Answers 515 = DXV
1005 = MV
32 = XXXII
9= IX