Workshop was organized as part of CICM multiconference. It had two parts: MIR symposium and MIR happening. The Math IR Symposium is a traditional-style workshop with scientific contributions about mathematics information retrieval. Topics include but not limited to: MIR systems design and descriptions * requirements for mathematics information retrieval: use cases and typical queries * formula normalization, similarity, indexing and search algorithms * mathematics retrieval corpora preparation and tagging * semantically enhancing mathematical corpora for IR (from math OCR or presentation MathML in DML) * extracting semantic relations from corpora. * evaluation of MIR (methods and test corpora). The MIR 2012 workshop featured a friendly competition for the systems presented at the workshop. Since math information retrieval is still quite young and developing, we will not make this an official competition, but a happening, where we get together and test our system on a common set of problems. We expect the happening to transcend the workshop proper. The aim of the MIR happening was jointly gain a better understanding into the information retrieval needs of mathematicians and the respective strengths and weaknesses of the respective IR approaches and systems. As a tangible result of the happening the organizers will compile a survey paper and report of this newly-gained understanding. In particular, it was not an aim of the MIR happening to determine "winners" of the competition in any form. That may be an aim of a subsequent competition, when we have a better grip on the problems and possible evaluation approaches.