Elementary school students' prolonged experiences with positive numbers and operations often lead to their overgeneralizations of rules (e.g., adding always makes larger numbers, subtracting always makes smaller numbers). These overgeneralizations can make learning algebra more difficult later, particularly when students must simultaneously learn algebra, negative numbers, and operations with negative numbers. The purpose of this project is to design and develop educational games centered on negative number concepts that target students before they learn algebra in middle school. Earlier exposure to and learning about negative numbers could increase students' motivation, understanding of connections between positive and negative numbers, and preparation for algebra. In the long term, this earlier exposure could lead to later success in advanced mathematics and improve science technology engineering mathematics (STEM) education. The project team will design and develop the educational games through an iterative process of prototyping and testing. During the prototyping phase, the project team will consult with experts about how the games' mechanics and rules align with and support second- to fourth-grade students' learning of integer principles. Next, they will test the games with students. Based on students' interpretations and uses of the rules, their interaction with the materials, and their feedback, the research team will refine the materials. During the testing