### Numerals

The Romans used seven letters of the Latin alphabet to represent numbers. They used:

“I” for “1”

“V” for “5”

“X” for “10”

“L” for “50”

“C” for “100”

“D” for “500”

“M” for “1,000”

If the Romans needed to express other numbers, they combined symbols adding or subtracting their values, for example:

2 was represented by placing “I” and “I” together – II; 22 was therefore expressed by the combination “XXII”

If “I” was used before “V” or “X” it meant one less – 4 was represented by IV. “X” and “C” used before “L” or “C” and “D” or “M,” respectively, indicated ten/a hundred less – “XL” meant “40” while “CD” meant “400.”

### Zero

The Roman numeric system didn’t have a specific symbol denoting “zero.” However, the Romans were familiar with the concept of nothingness. For this purpose, they used the word “nulla” that meant “none” in Latin. By 525, the word was used alongside with other numerals and by 725 it was shortened to “N.”

### Fractions

Since it was more convenient to express fractions like 1/3 and 1/4 with the help of a duodecimal (base 12) system, the Romans applied it for fractions. Dots were used in fractional notation:

A dot (•) represented 1/12

Two dots (••) represented 2/12=1/6

Three dots (•••) represented 3/12=1/4

Four dots (••••) represented 4/12=1/3

Five dots (•••••) represented 5/12

The letter “S” that is a shortened variant of the word “semis” denoting “half” was used to denote 6/12=1/2

S• represented 7/12

S•• represented 8/12=2/3

S••• represented 9/12=3/4

S•••• represented 10/12=5/6

S••••• represented 11/12

I represented 12/12=1