Lesson: Introduces students to modular (clock) arithmetic and how modular arithmetic can be used to encode messages using simple shift, multiple and affine ciphers.

Lesson: Students practice arithmetic skills. Can be tailored for practice of all types of single operation arithmetic ranging from simple addition to operations with integers and decimals.

Activity: Students play a generalized version of connect four, gaining the chance to place a piece on the board by answering arithmetic questions (addition, subtraction, multiplication, division). Parameters: time, difficulty level, types of questions. Arithmetic Four is one of the Interactivate assessment games.

Activity: Arithmetic Quiz gives the user randomized questions to answer on arithmetic with whole numbers and integers. Parameters: Level of difficulty and types of questions. Arithmetic Quiz is one of the Interactivate assessment quizzes.

Activity: Students play a generalized version of connect four, gaining the chance to place a piece on the board by answering order of operations questions (addition/subtraction, multiplication/division, exponents, and parentheses). Parameters: time, difficulty level, types of questions. Order of Operations Four is one of the Interactivate assessment games.