# Browse

### José N. Contreras

### Enrique Ortiz

This article presents an example of discovering an idea through creative play. After some trial and error, I drew a wonderful image, which I later learned was a two-dimensional view of a four-dimensional shape called tesseract.

### Ruthmae Sears

### Derek A. Williams, Kelly Fulton, Travis Silver, and Alec Nehring

A two-day lesson on taxicab geometry introduces high school students to a unit on proof.

### Courtney K. Baker, Terrie M. Galanti, Kimberly Morrow-Leong, and Tammy Kraft

The Teaching for Robust Understanding framework facilitates online collaborative problem solving with digital interactive notebooks that position all students as doers of mathematics.

### Min Wang, Candace Walkington, and Koshi Dhingra

An example of an after-school club activity gives educators some tools and suggestions to implement such an approach in their schools.

### Amanda K. Riske, Catherine E. Cullicott, Amanda Mohammad Mirzaei, Amanda Jansen, and James Middleton

We introduce the Into Math Graph tool, which students use to graph how “into" mathematics they are over time. Using this tool can help teachers foster conversations with students and design experiences that focus on engagement from the student’s perspective.

### Atara Shriki and Dorit Patkin

Success in STEM fields depends largely on robust spatial skills, in particular on the ability to perform a mental rotation. Given that this ability can be nurtured, this article includes examples of diverse relevant tasks appropriate for grades 6–8 students.

### Jennifer Marshall

A series of tasks encourage students to reflect on the reasonableness of their number sense and use benchmarks to refine their estimations.