Distributed Computing via the Math-in-the-Middle Paradigm in OpenDreamKit. OpenDreamKit “Open Digital Research Environment Toolkit for the Advancement of Mathematics” - is an H2020 EU Research Infrastructure project that aims at supporting, the ecosystem of open-source mathematical software systems. From that, OpenDreamKit will deliver a flexible toolkit enabling research groups to set up Virtual Research Environments, customised to meet the varied needs of research projects in pure mathematics and applications. An important step in the OpenDreamKit endeavor is to foster the interoperability and distributed computing between a variety of systems, ranging from computer algebra systems over mathematical databases to front-ends. This is the mission of the integration work package (WP6). We report on experiments and future plans with the Math-in-the-Middle approach. This information architecture consists in a central mathematical ontology that documents the domain and fixes a joint vocabulary, combined with specifications of the functionalities of the various systems. Interaction between systems can then be enriched by pivoting off this information architecture.