Here’s a professional development solution in the form of a suite of web-based games designed to strengthen the mathematics knowledge of preservice and in-service elementary teachers, many of whom lack the mathematical understanding required to teach math. To engage elementary teachers in math and to introduce them to the benefits of educational gaming, PlatinuMath takes the form of a narrative-based adventure game with Steampunk art, a mystery narrative, 3D animation, and live video. The PlatinuMath learning system includes both conceptual and procedural gaming activities and is built to align with the U.S. Common Core Standards for elementary math. The Common Core key knowledge targets are delineated into implicit conceptual understandings and more explicit procedural skills through 23 mini-games. All mini-games are multi-leveled and carefully scaffolded into 6 levels of difficulty. A typical mini-game finds the story’s heroine and her Steampunk robot companion cornered by ravenous zombies, and, to escape they must use mathematical reasoning. Additional learning lessons provide more explicit explanations of the topics and can be accessed from the PlatinuMath interface after, during, or before gameplay. PlatinuMath, a formative assessment tool, works on mobile devices as well as personal computers. Check it out.