Understanding part-whole relations is crucial in early mathematics education. However, both analogue and digital learning environments often lack systematic approaches to foster part-whole understanding. With the rising popularity of educational apps, it is essential to evaluate how they implement learning of part-whole relations. Accordingly, this review aims to evaluate whether educational math apps provide a systematic approach to learn part-whole relations. Therefore, we first developed a framework for evaluating apps with a focus on opportunities for learning part-whole relations. Second, we applied this framework to evaluate n = 18 apps. Results indicated that none of the reviewed apps implemented a systematic approach to learn part-whole relations from hands-on to more abstract compositions/decompositions including number triples up to ten. In contrast, the automating of number compositions/decompositions is most frequently targeted. These findings underscore the importance of selecting educational apps carefully and integrating principles from effective learning environments and digital learning research into future app design.