Roman numerals were invented as the Romans needed a system in order to easily price different goods and services. Roman numbers were widely used throughout the Roman Empire in everyday life. Following the fall of the Roman Empire, numerals continued to be used throughout Europe up until the 1600's. The Romans adopted the numeral system from their predecessors in central Italy, the Etruscans, they simply made a number of changes to improve the system.
Roman Numerals Chart
Roman Numeral Converter
An Introduction to Numerals
Roman numbers are created by combining different Roman numerals together, these numerals are often written from left to right usually in descending order. For example; in order to make the numeral 12 we must take both the numerals for 10 (X) and 2 (II), which when combined make XII. However, this is no always the case, the Romans didn't want four of the same numerals recurring, so in order to prevent this they used subtraction. For example; the number 4 isn't represented by IIII, instead we subtract the Roman numeral for 1 (I) away from the Roman numeral for 5 (V), this gives us IV. Use the Roman numeral converter above to get a better understanding of the Roman number system.
In order to make the number 16 we must take the numerals for 10 (X), 5 (V) and 1 (I), thus making XVI.
In order to make the number 27 we must take the numerals for 20 (XX), 5 (V) and 2 (II), thus making XXVII.
In order to make the number 32 we must take the numerals for 30 (XXX) and 2 (II), thus making XXXII.
In order to make the number 58 we must take the numerals for 50 (L), 5 (V) and 3 (III), thus making LVIII.
In order to make the number 188 we must take the numerals for 100 (C), 50 (L), 30 (XXX) and 3 (III), thus making CLXXXIII.
In order to make the number 555 we must take the numerals for 500 (D), 50 (L) and 5 (V), thus making DLV.
In order to make the number 1582 we must take the numerals for 1000 (M), 500 (D), 50 (L), 30 (XXX) and 2 (II), thus making MDLXXXII.
Roman Numerals 1 to 10
The number one is represented by a single line.
The number two is represented by two lines.
The number three is represented by three lines.
The number three is represented by a single line followed by the numeral for five 'V'. A smaller number before a larger number tells us that we need to subtract the number. E.g. IV = 5-1 = 4
The number five is represented by the letter 'V'.
The number six is represented by a V and an I. This tells us that we need to add the numbers together. E.g. VI = 5+1 = 6
The number seven is represented by a V and two II's. This tells us that we need to add the numbers 2 and 5 together in order to get the Roman number 7.
The number eight is represented by the Roman numerals for V and three III's. Just like the numbers six and seven we add them together to get the number 8.
The number nine is represented by the Roman numerals for 1 (I) and 10 (X). Just like the number 4, because the I is before the X we subtract it, this gives us the number 9.
The number 10 is represented by the letter 'X'.
Rule 1 - Subtraction
The Romans didn't want four of the same symbols to recur in succession. In order to prevent this subtraction is used. For example; the Roman number for four is made by putting an 'I' in front of a 'V', this simply means 5-1. Here are some rules for bigger numbers.
⋅ I can be placed before V (5) and X (10) to make 4 and 9.
⋅ X can be placed before L (50) and C (100) to make 40 and 90.
⋅ C can be placed before D (500) and M (1000) to make 400 and 900.
The number 1904 is a great example of the above rules. The number 1904 is represented by the numerals MCMIV. If we break it down then; M = 1,000, CM = 900 and IV = 4. Use the Roman numeral converter above to find more examples of these rules!
Rule 2 - Large Numbers
As the system of Roman numerals developed there was a need for numerals to represent larger numbers. As a result, it was decided that a horizontal line on top of a numeral would represent one thousand times the value of that numeral. For example; 10,000 was represented by an X with a line across the top of it (10 x 1000 = 10,000). Use the Roman numeral converter above to write some larger Roman numbers.
Rule 3 - Fractions
Fractions were often used in currency. The most common fractions used were twelfths and halves. A twelfth is represented by a single dot '•', which is known as an 'uncia'. A half is represented by the Latin letter 'S', which is short for semis.
Rule 4 - Zero
This isn't really a rule, but interestingly, there is no numeral to represent zero. This is because the system of Roman numbers was developed as a means of trading and there was no need for a numeral to represent zero. Instead they would have used the Latin word 'nulla' which means zero.
Origin of Roman Numerals
There were a number of counting systems in the ancient world prior to the creation of Roman numbers. For example, the Etruscans, who lived in central Italy before the Romans, developed their own numeral system with different symbols.
A common suggested theory for the origin of the Roman numbers
system is that the numerals represent hand signals. The numbers; one, two, three and four are signalled by the equivalent amount of fingers. The number five is represented by the thumb and fingers separated, making a 'V' shape. The numbers; six, seven, eight and nine are represented by one hand signalling a five and the other representing the number 1 through to 4. The number ten is represented by either crossing the thumbs or hands, signalling an 'X' shape.
The second theory suggests that Roman numerals originate from notches which would be etched onto tally sticks. Tally sticks had been used for hundreds of years previous to the Romans and were still used up until the 19th century by shepherds across Europe.
The numbers one, two, three and four were represented by the equivalent amount of vertical lines. The number five represented by an upside down 'V'. The number was represented by an 'X'. In order to make larger numbers they would use the same rules as numerals did.
For example; seven on a tally stick would look like: IIIIVII, when shortened it would look like VII, identical to Roman numbers. Just like the above example the number seventeen, in long form, would look like IIIIVIIIIXIIIIVII, this in short form would look like XVII, which is also identical to numerals.
Certain Roman numerals; for example, four when written on a tally stick would like this: IIIIV. When the tally was re-written at a later date four could be written as either IIII or IV. As the Roman number system was developed further it adapted the number 50 to be represented by the letter 'L'. Similarly, the number 100 was illustrated by a wide array of symbols, most commonly, represented by the numeral 'I' on top of an 'X'.
The numbers 500 and 1000 were represented by a 'V' and 'X' in a circle respectively. As the Roman Empire grew these symbols were replaced with a 'D' (500) and 'M' (1000). The Latin letter M was short for 'mile', which is translated as one-thousand.
Modern Use of Roman Numerals
Despite Arabic numbers being used predominantly in today's world, numerals can be commonly found in different places. For example;
• Numerals are often used to distinguish between monarchs. For example; Henry VII and Henry VIII.
• Numerals are often found on clocks and other timepieces.
• Numerals can be found on buildings to illustrate the year of construction.
• Numerals are also used in the Olympic Games. The Olympic Games in Brazil will be the 31st Olympics, use the Roman numeral converter above to work out the numeral.
Other Number and Counting Systems
Prior to Romans numerals there were many civilisations who had invented and used their own counting and number systems. We are going to take a quick look at Egyptian, Babylonian and Arabic number mechanisms.
Egyptian numbers: 3000-1600BC
One of the oldest number systems we have comes from ancient Egypt, with the earliest record being recovered from 3000BC, over 5000 years ago. The Egyptian counting system was very comprehensive compared to others, they even had a symbol to represent infinity!
In this system the number 1 was represented by a straight line, just like Roman numerals. The number 10 is represented by a semi-coiled length of rope and 100 being represented by a coiled rope. As the numbers get larger they are represented by other symbols. The number 1,000 is illustrated using a water lily or lotus. The symbol for 10,000 is a large upward facing finger. The figure 10,000 is represented by a frog and finally 1,000,000 is represented the Egyptian god Heh.
The Egyptians unlike the Romans didn't use the subtraction rule, instead they would just use the symbols for 1, 10, 100, 1,000 and so on. For example; the number 3 is illustrated by 'III', similarly the number 9 is represented by 'IIIIIIIII'.
Babylonian numbers: 1750BC
The Babylonian number system was one of the more complicated arithmetic systems. The Babylonian civilisation adopted the system from another much older civilisation, the Sumerians. Similar to Roman numerals there is no figure to represent zero. Another major flaw in this system is that the symbol for both one and sixty are the same!
Similar to the Egyptian numeral system 1 to 9 would be represented by the equivalent amount of single units. For example; the number 3 is written as . This is the same for multiples of 10 and thus the number 20 is written as . Using these examples we can make the number 23, which is written as .
Similar to Roman numerals there is no figure to represent zero. As we use one to ten as our base, the Babylonians would use one to sixty, furthermore the symbols for one and sixty were the same!