Khmer numerals

Khmer numerals ០ ១ ២ ៣ ៤ ៥ ៦ ៧ ៨ ៩ are the numerals used in the Khmer language. They have been in use since at least the early 7th century.

Having been derived from the Hindu numerals, modern Khmer numerals also represent a decimal positional notation system. It is the script with the first extant material evidence of zero as a numerical figure, dating its use back to the seventh century, two centuries before its certain use in India. Old Khmer, or Angkorian Khmer, also possessed separate symbols for the numbers 10, 20, and 100.

Each multiple of 20 or 100 would require an additional stroke over the character, so the number 47 was constructed using the 20 symbol with an additional upper stroke, followed by the symbol for number 7. This inconsistency with its decimal system suggests that spoken Angkorian Khmer used a vigesimal system.

As both Thai and Lao scripts are derived from Old Khmer, their modern forms still bear many resemblances to the latter, demonstrated in the following table:

The spoken names of modern Khmer numbers represent a biquinary system, with both base 5 and base 10 in use. For example, 6 (ប្រាំមួយ) is formed from 5 (ប្រាំ) plus 1 (មួយ).

With the exception of the number 0, which stems from Sanskrit, the etymology of the Khmer numbers from 1 to 5 is of proto-Austroasiatic origin.

Whilst Vietnamese vocabulary is very Sinicized, the numbers 1-5 retain proto-Austroasiatic origins.

The numbers from 6 to 9 may be constructed by adding any number between 1 and 4 to the base number 5 (ប្រាំ), so that 7 is literally constructed as 5 plus 2. Beyond that, Khmer uses a decimal base, so that 14 is constructed as 10 plus 4, rather than 2 times 5 plus 4; and 16 is constructed as 10+5+1.