In an age where information is increasingly transmitted via electronic formats, maintaining the accuracy of information is crucial. Whether this information is as simple as a book on loan from a library or as important as a bank account number, maintaining consistency when transmitting information is essential to avoiding monetary or organizational errors. To maintain consistency in various information transfers, check digit systems based on number theory are used to detect errors. This article will examine the value of check digit schemes in light of their application and mathematics. To begin, a basic understanding of check digit patterns reveals the value of this application of number theory. Check digit systems exist in almost all identification numbers. Authors Pommersheim, Marks, and Flapan (2010) noted that there are common examples of check digit systems in ISBN numbers, airline tickets, money orders, and barcodes on retail items . From these examples, it is clear that number control schemes are a common application of number theory that has a discrete impact on everyday life. This impact is reflected in the function of check digit schemes. In summarizing this function, mathematics professor Joseph Kirtland (2001) noted that "most check digit systems add one or more additional digits, called check digits, to the identification number and then use the digit(s) to check. for errors after transmitting the number” (p. 5). According to the author's overview, the impact of check digit systems is found in the prevention of errors that accompany their use. By implementing a check digit system in a computer or scanner, the device can quickly verify the validity of an identification number and report or co...... middle of paper ..... . electronic devices. Additionally, the systems prevent errors in libraries, commerce and identification. Finally, the mathematics of check digit schemes is interesting and helps detect various transfer errors. Understanding check digits is useful for understanding the modern world. The average person possesses various forms of identification and engages in many activities that involve identification. Ensuring proper identification is essential to preventing monetary or identity errors. Works CitedKirtland, J. (2001). Identification numbers and check digit schemes. Washington: Mathematical Association of America. Pommersheim, JE, Marks, TK and Flapan, EL (2010). Number Theory: An animated introduction with proofs, applications, and stories. Hoboken, NJ: Wiley. Wheeler, M. L. (1994). Check digit schemes. The math teacher, 87(4), 228-230.