This paper draws attention to the growing adoption of web and mobile apps in the enterprise, typically supported by digital storage in the cloud. While these developments offer several advantages, they also pose challenges for workers who must make sense of increasingly complex software configurations – with apps accessible from multiple devices (typically supporting different features or capabilities) and used alongside legacy enterprise software. We investigate how workers navigate these environments through a qualitative study of the work practices of employees in an app-enhanced organization. Our findings focus on two sets of practices. The first involves appraising what software programs and software/device combos offer what features, what we refer to as software calculus. The second involves orienting towards data formats and database structures that underlie specific software programs and their interactions with specific devices, what we label data thinking. Building on prior work on the role of materiality in CSCW, our findings set out a call for further attention to the material and lively dimensions of software and the emergent challenges they pose for contemporary work practices.