Sinhala numerals, are the units of the numeral system, originating from the Indian subcontinent, used in Sinhala language in modern-day Sri Lanka.
Numerals or numerations around Kandyan Kingdom
It had been found that five different types of numerations were used in the Sinhala language at the time of the invasion of the Kandyan kingdom by the British. Out of the five types of numerations, two sets of numerations were in use in the twentieth century mainly for astrological calculations and to express traditional year and dates in ephemerides. The five types or sets of numerals or numerations are listed below.
Sinhala archaic numerals or Sinhala Illakkam
Abraham Mendis Gunasekera, in A Comprehensive Grammar of Sinhalese Language (1891), described a set of archaic numerals which were no longer in use. According to Mr. Gunesekera, these numerals were used for ordinary calculations and to express simple numbers. Gunasekera wrote: The Sinhalase had symbols of its own to represent the different numerals which were in use until the beginning of the present century. Arabic Figures are now universally used. For the benefit of the student, the old numerals are given in the plate opposite (No. iii.).
Sinhala numerals did not have a zero and they also did not have zero concept holder. They included separate symbols for 10, 40, 50, 100, 1000.
These numerals were also regarded as Lith Lakunu or ephemeris numbers by W. A. De Silva in his Catalogue of Palm leaf manuscripts in the library of Colombo Museum. This set of numerals was known as Sinhala illakkam or Sinhala archaic numerals.
Sinhala numerals or Sinhala illakkam were used in the Kandyan convention which was signed between Kandyan Chieftains and the British governor, Robert Brownrig, in 1815. Eleven clauses were numbered in Arabic numerals in the English part of the agreement, and the parallel Sinhala clauses were numbered in Sinhala archaic numerals.
Sinhala astrological numerals or Sinhala Lith Illakkam
Although this numeral set was commonly used for casting horoscopes and to carry out astrological calculations, it had been found that this set had been used for numbering pages of Ola palm leaf books which covered primarily of non-Buddhist topics in Sinhala. Numbers of lith illakkam look Sinhala letters and vowel modifiers, and it had been discovered that there are mainly two versions of these illakkam according to the way numbers 2, 3 and 9 are written. The number six is known as ‘akma’ in the Lith Illakkam. These numerals were in use continuously for writing horoscopes on Ola leaf, the tradition of which continued till the beginning of the twentieth century. Both versions of Lith illakkam have a zero and the zero is the Halantha or Hal lakuna (kodiya) in the Sinhala language. Although it is not understood whether Sinhala mathematicians treated zero as a number, it was quite possible they had known the concept of zero. In Lith Illakkam, numbers greater than zero were written the same way as the Arabic numbers with the zero and the value of the number in the left was increased by ten. In other words, Lith illakkam had a zero and a zero place holder concept. Lith illakkum version 1 had for 2, 3 and 9, Sinhala letter ‘Murthda Na’ in 6 to 8th century. In the second version of Lith Illakkam as W. A. De Silva had depicted in his book, 2,3 and 9, Sinhala letter, ‘Na’ (න) with vowel modifiers.
One of the most interesting articles which had been discovered is an article on numerals and numerations in Sinhala language, the authorship of which has been attributed to Abrham Mendis Gunesekera. In this article, he refers to Lith Illakam as well as to Sinhala Illakkam. For Sinhala illakkam, he produces the same shapes which had been given in his English book. Abraham Mendis Gunesekera uses modern Sinhala letters and vowel modifiers which is the Version 2 of Lith illakkam. In this article, he clearly mentions that Hal lakuna or ‘Kodiya’ is the zero. In other words, ‘Sunayathana’ is filled with a kodiya will multiply by ten of the number which is on the left side of Sunayasthana. Abrham Mendis Gunesekera clearly states that instead of Hal lakuna of the Sinhala language, a ‘Shunaya binduawa’ (zero) can be used to fill the ‘Shunayasthana’ (Zero Place Holder). In other words, Lith Illakkum uses duality of zero to write numbers greater than 9.