Mathematical apps are now used in many school settings. To support teachers in making appropriate pedagogical decisions regarding their increased use, empirical, quantitative analyses of apps are required. This chapter initially explores how cluster analysis can be used to identify elements within individual apps so that similar apps may be grouped together. This will assist teachers to make decisions regarding which apps might be most appropriate, either singularly or in groups, for various elements of their practice. Based upon selection criteria and ranking via four criterion-based scales, the cluster structure of 57 apps, primarily supporting number and algebraic thinking in elementary mathematics classrooms, is reported. The chapter then explores the homogeneity and heterogeneity of these clusters of apps and indicates when and how these apps may be used to enhance student mathematical learning. The chapter therefore makes both methodological and pedagogical contributions to the broader discussion of the use of apps in primary mathematics classrooms.