for electric, radio, and digital communication, such as Morse code. They are encoded in ASCII at positions 0x30 to 0x39. Masking to the lower four binary bits (or taking the last hexadecimal digit) gives the value of the digit, a great help in converting text to numbers on early computers. These positions were inherited in Unicode. EBCDIC used different values, but also had the lower 4 bits equal to the digit value. Comparison with other digits See also Arabic numeral variations Regional variations in modern handwritten Arabic numerals Seven-segment display Text figures Explanatory notes Citations General and cited sources Further reading External links Lam Lay Yong, "Development of Hindu Arabic and Traditional Chinese Arithmetic", Chinese Science 13 (1996): 35–54. "Counting Systems and Numerals", Historyworld. Retrieved 11 December 2005. The Evolution of Numbers. 16 April 2005. O'Connor, J. J., and E. F. Robertson, Indian numerals . November 2000. History of the numerals Arabic numerals Hindu-Arabic numerals Numeral & Numbers' history and curiosities Gerbert d'Aurillac's early use of Hindu-Arabic numerals at Convergence Numerals