Join the Cryptokids as they apply basic mathematics to make and break secret codes. This book has many hands-on activities that have been tested in both classrooms and informal settings. Classic coding methods are discussed, such as Caesar, substitution, Vigenère, and multiplicative ciphers as well as the modern RSA. Math topics covered include: - Addition and Subtraction with, negative numbers, decimals, and percentages - Factorization - Modular Arithmetic - Exponentiation - Prime Numbers - Frequency Analysis.The Cryptoclub presents a number of different systems of encryption and methods of breaking them. Each type of cipher is presented in detail and exercises are included allowing students to apply the techniques presented. The Cryptoclub also includes short descriptions of famous examples of secret codes, including the Beale Ciphers, the Zimmerman telegram, and the German Enigma cipher.The accompanying workbook provides students with problems related to each section to help them master the concepts introduced throughout the book. A PDF version is available at no charge from the publishers.