This Small Business Innovation Research (SBIR) Phase I project focuses on the design and testing of graphical, collaborative games within a virtual world environment to support math learning for elementary school students. Numedeon, Inc. is the creator of Whyville, the award winning educational virtual world for children ages 8 to 15. Whyville has engaged 7 million users in science and math explorations since 1999, with 200,000 monthly uniques spending 30+ minutes on average per visit. Numedeon brings its experience in creating collaborative, open-ended learning games to this project, building online games and experiences upon specific components of the ThinkMath! curriculum. ThinkMath! is an innovative K-5 mathematics curriculum developed by Education Development Center (EDC) with prior support from the National Science Foundation. Pooling expertise from consultants at EDC, WestEd, and DaVinci Minds, Numedeon will address three fundamental challenges in the effective use of games in formal education: providing scaffolding and assessment without compromising game play and engagement, leveraging collaboration and user creation to promote in-depth understanding, and designing integrated tools for training and supporting teachers. The resulting pilot games along with teacher tools and embedded assessment will be launched in Whyville for testing and evaluation. The broader impact/commercial potential of this project lies in creating a new form of interactive learning that integrates formal classroom-based instruction with informal game-based learning within an online social environment. As the $6.2 billion textbook market in the US goes digital, this project challenges the mindless conversion of print curriculum to digital textbooks and drill-based practice of ?math facts? while addressing a critical national need to promote mathematics competency. By combining the best in curriculum development (EDC) with the best in collaborative game-based learning (Numedeon), this effort to bring a standards-based mathematics curriculum into a successful commercial virtual world is first of its kind. It will set a standard for thoughtfully marrying curriculum with digital medium to create a high value, high visibility product that goes beyond rote memorization and drilling to building mental infrastructure and mathematical understanding. In addition, the visual nature of game-based instruction will reduce barriers to use for bilingual and special needs students. Finally, teacher professional development and support tools designed as part of an integrated process, as opposed to tacked-on as an afterthought, will have significant pedagogical impact and market potential