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Math: Roman Numerals - Tutorial
This section will cover the fundamentals and rules of writing Roman numerals.
How Roman Numerals Are Used
Roman Numerals Chart
Here are just a few Roman numerals to give you an idea of how they are written.
I (1)
V (5)
X (10)
L (50)
Roman numerals are written from left to right.
A smaller number is placed before a larger number to show that the smaller
number is subtracted from the larger number.
Example 1:
Rules for Roman Numerals
V = 5
IV = 4
X = 10
IX = 9
L = 50
LX = 60
1.
2.
3.
4.
5.
6.
7.
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
XIII
XIV
XV
XVI
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
140
150
160
170
180
190
200
17
18
19
20
30
40
50
60
70
80
90
100
110
120
130
XVII
XVIII
XIX
XX
XXX
XL
L
LX
LXX
LXXX
XC
C
CX
CXX
CXXX
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
15,000
25,000
50,000
100,000
1,000,000
5,000,000
10,000,000
300
400
500
600
700
800
900
CXL
CL
CLX
CLXX
CLXXX
CXC
CC
CCC
CD
D
DC
DCC
DCCC
CM
M
MM
MMM
Just for Practice
Let's say that we want to write 2,874 using Roman numerals. We would begin by writing each part separately.
2,874
MM (1,000 + 1,000 = 2,000)
DCCC (500 + 100 + 100 + 100 = 800)
LXX (50 + 10 + 10 = 70)
IV (5 - 1 = 4)
Then we would put it all together.
MMDCCCLXXIV = 2,874
Below are some examples for when to use a vinculum.
This time, let's say we want to write 3,872,649.
The Romans used certain alphabets to represent their numbers.
- hours on a clock
- key topics in an outline
- a series of certain annual sporting events
- the copyright date of television programs or movies
These numbers are called Roman numerals. Roman numerals are still used in modern society to show:
C (100)
D (500)
M (1,000)
L = 50
X = 10
A vinculum, or horizontal line, is placed over a number to multiply that number
by 1,000.
When two numbers are multiplied by 1,000, the vinculum is extended over
the two symbols, and so on.
When subtracting using Roman numerals, write the smaller numeral first followed by the larger numeral.
Example 5: Writing IV is like saying:
5 - 1 = 4 instead of 1 - 5.
A smaller number is placed after a larger number to show that the smaller number is added to the larger number.
Example 4:
If we want to write 60, we will place the symbol for 10 to the right of our symbol for 50.
To write the symbol for 40, place an X to the left of the L.
Example 2:
XL = 40
Fours and nines are written to the left with the principle of subtraction as
shown below.
Example 3:
1.
2.
3.
