In this report, we describe a survey of mathematics education apps in the Apple App Store, conducted as part of a research project to develop a tablet-based assessment prototype for elementary mathematics. This survey was performed with the goal of understanding the design principles and techniques used in mathematics apps designed for tablets. We focused our reviews on four areas, (1) the quality of mathematical content, (2) feedback and scaffolding, (3) richness of interactions, and (4) adaptability of the applications. These four areas were cultivated from prior research on digital tools in mathematics (e.g., Digital Tools for Algebra Education criteria; Bokhove & Drijvers, 2011), designing principles of learning objects (e.g., Learning Object Evaluation Metric; Kay & Knaack, 2008), as well as quality of mathematics instruction (e.g., Hill et al., 2008). We end with recommendations for tablet assessment design cultivated through this review.