The Common Core State Standards include functions starting in 8th grade, and throughout high school. I support that emphasis.
Over the years, I have developed chunks of curriculum at all those levels. See if any of the links below take you to something you can adopt or adapt for your classes.
8th Grade
Basic Algebra
Algebra: Themes, Tools, Concepts contains many lessons on functions.
Use this index to find dozens of lessons on:
- Direct and inverse variation
- Exponential functions
- Linear functions
- Quadratic functions
- Slope and rate of change
- Square root
See also:
Algebra 2 and Beyond
- Sine Curve
- `n^(th)` Power Variation | Teachers' Guide
- Inverse Variation
- Exponential Functions
- Logarithms
- Graphing Square Roots