Moving beyond memorization of probability rules, the area model can be useful in making some significant ideas in probability more apparent to students. In particular, area models can help students understand when and why they multiply probabilities and when and why they add probabilities.

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### Kelly Hagan and Cheng-Yao Lin

April 2020's GPS department provides tasks for each grade band that invite students to reason with age-appropriate number theoretic concepts.

### Erell Germia and Nicole Panorkou

We present a Scratch task we designed and implemented for teaching and learning coordinates in a dynamic and engaging way. We use the 5Es framework to describe the students' interactions with the task and offer suggestions of how other teachers may adopt it to successfully implement Scratch tasks.

### Stefanie D. Livers, Kristin E. Harbour, and Lindsey Fowler

In our attempts to make a concept easier, we may hinder student learning.

### 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.

### Megan H. Wickstrom, Elizabeth Fulton, and Dacia Lackey

Use those multicolored linking bricks to help students connect measurement with an understanding of number and operations as well as fractions.

### Stephen Phelps

### Edited by Anna F. DeJarnette

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

### Jennifer Suh, Sara Birkhead, Rachelle Romero Farmer, Terrie Galanti, Alexandrea Nietert, Tyler Bauer, and Padmanabhan Seshaiyer

Working with a mathematics coach and university researchers in a K-4 lesson study, teachers increase their understanding of student abilities in a fair-share sandwich problem.