In this article, the authors share how gameplay with dominoes can leverage students' quantitative reasoning to promote number development and additive reasoning. This article explores three domino games (Basic Dominoes, Just Before/Just After, and Ten Train), and considers the following: (1) rules and details; (2) students' subitizing and unit construction and coordination; and (3) teachers' questions, students' productive struggle, and content standards. By intentionally connecting gameplay with dominoes to students' number and operation construction, the authors illustrate how educators can leverage students' game strategies to support the development of mathematical reasoning (NCTM 2014).