## ALGI.4 Functions

### Decoder Ring

What are some ways to encrypt secret messages? Students explore function concepts using ciphers to encrypt messages both graphically and algebraically; they try to decrypt some messages too. In the end, they’ll learn what makes for a useful cipher, and what makes a cipher impossible to decode.

Topic: Building Functions (BF), Functions (F), Interpreting Functions (IF)

### It's a Date

How can we improve our calendar? Students examine some other ways to keep track of dates, and use number sense and function concepts to convert between different calendars.

Topic: Building Functions (BF), Functions (F), Interpreting Functions (IF)

### Romeo & Juliet

How does two people's love for one another change over time? Students investigate the effect of coefficients on recursive functions, and explore whether or not romance can be modeled with mathematics.

Topic: Interpreting Functions (IF), Seeing Structure in Expressions (SSE)

### Carpe Donut

How much should people pay for donuts? Students use linear, rational, and piecewise functions to describe the total and average costs of an order at Carpe Donut.

Topic: Building Functions (BF), Interpreting Functions (IF)