Lesson: Introduces students to modular (clock) arithmetic and how modular arithmetic can be used to encode messages using simple shift, multiple and affine ciphers.
Activity: Encode and decode messages to determine the form for an affine cipher. Input a message to encode, then input your guesses for the constant and multiplier. Caesar Cipher II is one of the Interactivate assessment explorers.
Activity: Decode encrypted messages to determine the form for an affine cipher, and practice your reasoning and arithmetic skills. Input your guesses for the multiplier and constant. Caesar Cipher III is one of the Interactivate assessment explorers.
Activity: Explore perimeter through rectangular and straight-line arrangements of tables, calculating the number of chairs needed to surround different arrangements. Tables and Chairs is one of the Interactivate assessment explorers.