\([cf(x)]' = cf'(x)\)

Conclude by giving your students these challenges:

- From All Corners by NRICH
- Picturing Triangular Numbers by NRICH
- Partly Painted Cube by NRICH
- Encircling by NRICH
- 2009 AMC 8, Problem 11
- Pinwheel Area

\([cf(x)]' = cf'(x)\)

Conclude by giving your students these challenges:

- From All Corners by NRICH
- Picturing Triangular Numbers by NRICH
- Partly Painted Cube by NRICH
- Encircling by NRICH
- 2009 AMC 8, Problem 11
- Pinwheel Area