This hands-on task, featuring differentiation and open-ended learning, sets up students to discover area models for themselves. Organized around NCTM’s eight teaching practices from *Principles to Actions*, this article describes the task’s setup and implementation.

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### Corinne Thatcher Day

### Lara K. Dick, Allison W. McCulloch, and Jennifer N. Lovett

A framework to guide teacher noticing when students are working in technology-mediated learning environments.

### Stephen Phelps

### Edited by Anna F. DeJarnette

A monthly set of problems targets a variety of ability levels.

### P. Reneé Hill-Cunningham

Hundreds of species of animals around the world are losing their habitats and food supplies, are facing extinction, or have been hunted or otherwise negatively influenced by humans. Students learn about some of these animals and explore multiple solution strategies as they solve this month's problems. Math by the Month features collections of short activities focused on a monthly theme. These articles aim for an inquiry or problem-solving orientation that includes four activities each for grade bands K–2, 3–4, and 5–6.

### Stephen Phelps

### Edited by Anna F. DeJarnette

A monthly set of problems is aimed at a variety of ability levels.

### Michelle L. Meadows and Joanna C. Caniglia

Imagine that you and your language arts colleagues are teaching Edgar Allan Poe's short story, “The Pit and the Pendulum.” This thrilling story takes us to the Inquisition during which a prisoner is surrounded by hungry rats and bound to a table while a large pendulum slowly descends. The prisoner believes that the pendulum is 30-40 feet long and estimates that it should take about 10-12 swings before he is hit, leaving him with about a minute or a minute and a half to escape. Are his estimations correct? If so, will he make it out in time?

### James Hiebert, Dawn Berk, Emily Miller, Heather Gallivan, and Erin Meikle

We investigated whether the mathematics studied in 2 content courses of an elementary teacher preparation program was retained and used by graduates when completing tasks measuring knowledge for teaching mathematics. Using a longitudinal design, we followed 2 cohorts of prospective teachers for 3 to 4 years after graduation. We assessed participants' knowledge by asking them to identify mathematics concepts underlying standard procedures, generate multiple solution strategies, and evaluate students' mathematical work. We administered parallel tasks for 3 mathematics topics studied in the program and one mathematics topic not studied in the program. When significant differences were found, participants always performed better on mathematics topics developed in the program than on the topic not addressed in the program. We discuss implications of these findings for mathematics teacher preparation.

### Lisa L. Poling, Nirmala Naresh, and Tracy Goodson-Espy

Real-life scenarios embedded in social, cultural, historical, and political contexts can help bridge a gap between critical mathematics education and mathematical modeling.

### Annette Ricks Leitze, Stephanie Hodge, Danielle Houser, and Clint Mathews

**Animals that are at risk** of becoming extinct are called *endangered species*. They can be very large animals, like a polar bear, or very small, like a monarch butterfly. Learn about several different endangered species by engaging in these math activities.