Ithkuil uses a base 100 numeral system with roots for the numbers 1 to 10, and a stem-specific derivative suffix used with a number root to add a multiple of 10, providing the numerals up to 99. Ithkuil did not originally use the concept of zero. Numbers greater than 100 are expressed through multiple formatives, and a special numerical script has logograms for the numbers 1 to 100 and exponential powers of 100. On 27 March 2015, Quijada released a mathematical sublanguage using a dozenal number system which uses the circle constant tau.